I have long been wanting to explore the area known as Bacculite Mesa near Pueblo, Colorado searching for various fossils in the Pierre Shale deposits. This site is on private land but the land owner does allow clubs to visit on planned trips. This year I was able to make the field trip with the Canyon City and Lake George clubs.
The Western Interior Seaway had Colorado as the ocean floor around 70-80 million years ago. This was before the mountains were formed and all over Colorado there are fossils contained in Pierre Shale deposits. I have found pyrite and marcosite concretions in this general area coming out of the Pierre Shale. This is a rare and premiere location for fossils from this era of our geologic history!
Looking SW over Pueblo towards the Spanish Peaks from the Bacculite Mesa.
Thanks David for taking this picture of me and the Pierre Shale formations of Bacculite Mesa locality.
I carpooled with another fossil enthusiast David (thanks for the ride and company!) and we both had a great day and some amazing finds. David suggested hitting the back side of the collecting area and we found some great fossils in that area; but limited bacculites which was mainly on a different face of the mesa.
Collecting area we were in. Photo courtesy of David Gillard.
I found the bacculite fossils pretty much in every zone of these hills including on top, especially in the small ravines and in wash outs below the hills. I dug in a couple of spots that had quite a few rocks and fossils in the area, but didn’t find anything in-situ.
Various bacculites are common if you look through the alluvial slopes as they have weathered out of their host Pierre Shale and made their way down the hill. These multicolored bacculites are 4-6 inches long.
This is a bacculite tail that can flex, it is interlocked like vertebrae.
Here is what bacculites looked like. Taken from http://www.bhigr.com/media/photos/rplca/bacculites_grand.jpg
I found a couple spots where there was calcite (?) crystals in the fossils, like you see in the clams from Florida or septarian nodules. These were eroding out of harder rock and not the Pierre Shale, I’m assuming some kind of reef as the rock was full of imprints of fossil clams, shells and ammonites.
Shell imprint in shale.
Small clam Nymphalucina occidentalis
Weathered bacculite with shale matrix attached.
Unknown concretion, love the red/yellow/orange staining and patterns!
Little conglomerate ball, about an inch.
I love this triangle shell in a partial cube!
Calcite cluster, about 3 inches.
Veins of calcite mineralization
I believe this is the head of a small bacculite–which you can see protruding from the left side.
More calcite (?) crystallization
Bacculite with some of the iridescent patterns
Fossil clam with calcite mineralization
Some of the larger calcite (or barite?) crystals. These were beautiful amber color and translucent and in some spots gemmy. Up to an inch.
Prickly Pear Cactus were in bloom!
David found this bacculite head right away; preserved in matrix!
David’s ammonite fossil.
Cool color and design on this shale rock; about 4 inches.
Various clams and shells. Many have calcite cores.
This summer was great, but different than previous, for picking and rockhounding. My club field trip availability was limited–I led two trips and was able to make only one other. I went to Gem-o-rama in California with a rockhound buddy (see other blog post for that adventure). The remainder of my rockhounding trips this summer revolved around a pocket I uncovered during one of the club field trips I went on. I didn’t get out nearly as many times as I have in previous years; but the times I did get out were all high quality, extremely fun and productive! 2016 I would say it was a very successful season!
NOTE: As always, click on the pictures for a HD version. Trust me, it’s worth it! The videos are all available in HD as well.
On my third club field trip of the year I hit into a pocket that consumed 5 days of hard and thrilling work in the following month. It was the biggest crystal pocket I’ve ever found and had some really interesting and amazing crystals. It took me until the very last day of digging to think of the proper name for this pocket…over the month I continually thought about the pocket and realized I had a crush on it…and most of the crystals were damaged due to ancient violence, so I figured the name “Crush” described the experience perfectly!
Here is a _very_ rough drawing of the pocket. Note I have little artistic skills, lol! You can see where I entered in the upper right. The crystal pocket measured about 4 meters long, 0.6 meter diameter and the bottom was 1.5 meters underground.
It all started with a test hole about a meter from the pocket. From others’ experience in this area I knew that crystal pockets tended to be rather deep, so all my test holes need to go at least 1/2 meter deep. When the hole was about a meter diameter, I started to see a shift in color of the soil to a darker brown so I followed it–it was a subtle sign, but something “different” is often what leads you on the crystal trail! Not too much further I started to get into small chips of quartz which quickly turned into a layer of small quartz chips. These chips had no faces or flat sides. Breaking through that layer I entered a zone of darker material and started finding crystal faces. I was in the top of the pocket!
The first crystal plate/cluster I pulled out of the top of the pocket. I’d say that is a good sign of things to come!
This whole top and side of the pocket (along most of its length, except the ends) was softer clevlandite/feldspar material with large chunks of quartz buried here and there within; these quartz plates had beautiful secondary growth clear quartz all over one side, but in this layer nothing was fully euhedral. This layer of the pocket was about 10-25 centimeters thick and produced some nice plates of parallel growth clear quartz.
I continued to follow this trend horizontally (to bottom and right in the above diagram) until I reached the end of the pocket material — I was back into normal top soil-dirt and gravel underneath. That is when I started to excavate straight down. It was just a few minutes and then I hit extremely red pocket dirt/mud material which is the tell-tale sign of a crystal pocket! For the rest of the day I continued to pull out more of the same type of secondary growth plates and individual crystals with secondary overgrowth. Some really neat and unique crystals!
This was the largest plate I pulled out on the first day. The flow of the crystals is evident, this is about 30 cm wide. Note that the crystals change direction in the middle of the plate so they are pointing toward each other. I’m sure there is a reason for this, hit me up in the comments if you know why that would be! You’ll want to click on this image for a close up!
This is a really interesting crystal, I love the large terminated crystal surrounded with the smaller parallel growth, and then the different type of cluster growth at the bottom, first small then larger–all of this on the same plate! Also, the crystals at the very top are pointing down and immediately they reverse.
Thanks to Matt who was also on the field trip for taking this shot; I was back filling the hole as I progressed down. I was still only about 1/2 way through the depth of the pocket here. What an awesome day!
I thought I was nearing the end of the pocket at this time, so I buried the hole and packed up for the day knowing I’d come back in a few days, excavate the hole, and finish it off. It turned out not going the way that I planned…
Given the pocket was trending downwards, my plan for the second day was to remove the overburden over the deepest part of the hole and also widen the hole so I could continue picking crystals starting with a large crystal I already partially uncovered. Its good to have a plan, but its also good to be flexible! As I was mucking, I noticed that there was more of the pocket heading the other way (i.e. in the direction of the picture taker in the above shot). I ended up focusing on that direction for the entire day as the pocket continued, and got better (!!), in the opposite direction than I originally planned!
The pocket continued as described with the crystal plates at the top and side; but as I progressed I noticed that the floor of the pocket had a layer of larger more well formed crystals and finally microcline at the bottom before it ended up gravel. So I was now seeing the entire dimension of the pocket, about 2/3 meter tall and 1/2 meter wide.
An hour or so later, in the center of the pocket, the red mud/clay turned to purple in a couple of spots; that is when I started to find some small fluorite crystals. These fluorites were a truncated octahedron shape, kinda like a soccer ball. They started out really small (~1 cm) in single crystals but then out came out in small plates. A 1/4 meter further, along the side wall of the pocket, the fluorites started to get rather large, up to 8 cm. At the same time the bottom of the pocket had a couple of large quartz crystals.
This is one of the larger fluorite crystals I pulled out, definitely the largest on the second day. Note that the square sides do not have any coatings; but the other sides have a purple coating. Really interesting!
This is an example of a truncated octahedron. The fluorite crystals I found were very close to this, however only a few of the smaller ones were completely euhedral. The larger ones were about 1/2 of what is shown here.
This is the large quartz that was sitting on the bottom of the pocket. Three of the sides were covered in the secondary growth terminating with larger crystals at the top. It had a small cluster of fluorite on the right side, which was the direction where I was pulling out the fluorite mini-soccer balls. This was the largest crystal that came out of the pocket although it wasn’t euhedral!
The pocket didn’t show any signs of stopping, and all of a sudden it was dark. The nearly full moon was illuminating the ground through the trees. I was exhausted but needed to fill in the hole. So I started that tedious process and a little while later realized I was surrounded by coyotes…they must have killed something because they were screeching and barking in all directions! The whole experience made me think Edgar Allen Poe…the evening ended with the soundtrack of me filling in a large hole by the moonlight…what is going on in them woods after dark?
So as many of you that pick crystals know; when your into the crystals and have to leave a pocket, you continuously think about the pocket while waiting for your next trip! I’m no different and since I knew it was going to be a week before I could head back up, I couldn’t help but go through the fantasy scenarios and put together a plan of attack for that next trip. My plan was to excavate the far end of the pocket I was in day 1, taking out the overburden, widening the hole and pulling out the large crystal that was “stuck” and generally seeing how long that side of the pocket continued. Then, if I extinguished that side of the pocket, I would dig a new hole on the left side (again see diagram above) and meet up with where I left off after day 2. This would be less work by minimizing the mucking and centering the next portal along a new section of the pocket!
I had my plan and was able to take a day off of work a little over a week later. I decided I’d head up after work and set up camp, do the mucking of the hole and then go to sleep; waking up at the crack of dawn and start plucking crystals on my day off. Ended up getting a later start then I planned and it was dark by the time I arrived. I lit the lantern, set up camp, and then started the mucking which took a while. Of course, my plan was flawed because there is no way I can expose a crystal and not try to remove it! So I ended up working on the pocket until 2 am when my headlamp batteries started to dim! I then watched a meteorite shower and hit the sack.
The next morning I went down and continued with that side of the pocket until it pinched out. I was able to remove several large crystals (seen in the video) and behind these crystals the pocket pinched out. I hit nothing for the next 1/2 meter so I felt I reached that end of the pocket. After taking a break I started with phase two of my plan. I hit the end of my day 2 digs a couple of hours later and was back into the crystals. Once back into the pocket I was able to pull out a large chunk of fluorite along the side of the pocket (top side in the diagram). The fluorite came out in many pieces (totaling ~30 cm long, 5 cm tall and 5 cm wide). This was exciting because the fluorites were continuing to getting bigger the more I went in this direction! However, that was the last fluorite I found in the pocket. This large chunk was EXTREMELY brittle and broken up and much of it ended up disintegrating when I tried to rinse it off with water.
This was part of the large chunk of fluorite–the part that didn’t fully disintegrate when I was washing off the pocket mud!
These were some of the large crystals I pulled out right before the pocket pinched out on the right side. The crystal in the center is about 18 cm in diameter, has a lot of healed terminations, and fits perfectly with the other crystal that was found nearby in the pocket (see video)! These crystals do have damage–as most crystals did in this pocket (hence the pocket’s name)–but still was a thrill to find!
The hole after day 3, again back filling (on the right) to minimize the mucking efforts.
As you can see in the picture, it was awkward and difficult to go to the bottom of the pocket with that overburden there, so on day 4 I removed it. I then spent the remainder of that day taking out the bottom of the pocket and following it further. This section of the pocket started to change from the consistent topography I was getting used to. The top of the pocket had less of the softer clevlandite/feldspar than before and was more interlocked quartz and pegmatite. The number of crystals on the top was significantly less than before; the ones that I found were more euhedral and still coated with secondary growth. This side seemed to be where the most violence had occurred because there was a lot of damage to most of the crystals. The clay was also harder and pulling the crystals out without damaging them further made progress considerably slower. There was no more fluorite found on this side of the pocket.
After day #4, I added the wooden dam so I didn’t have to worry about the other side of the hole continuously filling in while I was mucking and working the pocket. I had started filling the hole before I took this picture, the bottom is another 1/3 meter buried.
The fifth day ended up being the final day. I was able to pull out a couple more really nice crystals as the pocket started to dive under a pegmatite rhine. The crystals below this point were no longer coated with secondary growth and all were intergrown and not fully euhedral. Many were still large. Once the pocket started to dive downward, the sides of the pocket were difficult digging and the crystals weren’t the quality to pursue further. The pocket had finally pinched out! I decided to throw in the towel and celebrate the amazing crystal pocket I had unearthed!
Here are the last crystals I pulled out before it got too uncomfortable to dig and the quality wasn’t worth pursuing any longer. The end of an amazing pocket!
Cleaning these crystals has been a chore. They had many phases of growth, first the smoky quartz, then a layer of albite, then a layer of iron oxide, then a layer of clear secondary growth quartz, then another layer of iron oxide and clay. Cleaning these requires a chemical bath and then mechanical cleaning, repeating over and over due to the tremendous amounts of facets that each crystal has. Because there is a layer of iron oxide under the clear quartz, the crystals are somewhat “spotted” with red and white that can’t be removed from under the clear quartz. In some instances they beg to be cleaned more, but then you realize that the staining is all under the clear quartz.
The amount of facets are amazing and each piece, regardless of how little or large–they are all unique! I will probably leave some pieces uncleaned as they will look better that way; while others I’ll spend the winter cleaning. It takes about 2-3 weeks per batch of crystals to get them clean enough for my liking (several iterations of chemical then mechanical cleaning), so it is a slow and labor intensive process. But a day playing with crystals is better than a day at work, that’s for sure! This will add some fun throughout the entire winter!
Here is a gallery of some of the crystals and plates that I found.
These were some of the large crystals I pulled out right before the pocket pinched out.
Last year I published an article How to Find Crystals that detailed some of the techniques I use and general prospecting tips, hoping to give several tips and hints to aid in expediting the learning curve of digging crystals. I’ve gotten some great feedback from that article and appreciate all the comments.
One of the things I tried to cover in that blog posting was what to look for on the surface and how to know if you are in a good spot and should continue digging, or bury the hole and continue the prospecting elsewhere. I knew it would be difficult to share that experience, as I’m still learning myself and it’s one of those things you can read about all day long but you don’t “get it” until you actually can see and experience how it is done. The pictures and text in that article were helpful I feel; but it still left me with questions after reading it–knowing that I had a plan for this year’s prospecting trips…
That blog posting was just the first of many postings I plan to do sharing what I’ve figured out on finding pegmatite crystals. I was able to get out digging late this spring and my goal was to take some video while I was on the hunt, hopefully showing what I look for on the surface and what I look for as I follow the pegmatite trail to the crystals (assuming I find crystals, which many times I don’t)! This video hopefully will provide some tips and hints of what works for me in the toughest part of the process, the initial prospecting and test holes.
Unfortunately due to leaving the camera in the sun too long, the pocket extraction video was corrupt, but the good stuff from a prospecting perspective was saved showing progress as I was hunting for the pocket. You’ll see that demonstrated in the video below.
I would love your feedback, questions and suggestions. I plan to do other videos showing different techniques.
The small crystal pocket I eventually hit I’m calling the OneTwo. It was mainly Microcline crystals, most were Carlsbad twinned! On these, once cleaned up, opposite faces had a blue tint of Amazonite to them; not as deep of green color as you find elsewhere in the region, but still really nice and a lot of fun. The smokey quartz I found all had secondary coatings of a darker colored quartz which will be very difficult to remove.
Interesting cluster of Amazonite / Microcline joined at a ~45 degree angle.
Carlsbad twinned Amazonite (light blue) with a small amount of cleavelandite sprays.
Nice little pair of Carlsbad twinned Amazonite with a bit of cleavelandite.
These are the largest crystals from the pocket, each about 3.5 inches tall. They had to be repaired as they came out in 3 pieces, the cap to the larger crystal was cleaved off and the two crystals had been separated and were found about a foot from each other in the pocket.
Smoky Quartz showing the secondary quartz growth. These have been soaked in a heated chemical bath for several weeks and look at lot better than they originally did; but this is as far as I will clean them as the quartz underneath is not worth the effort.
Some of the nicer twinned amazonites from the OneTwo pocket.
Examples of the coated smoky quartz from the OneTwo. The larger crystals are nearly 3 inches long. There were mostly microcline crystals in the pocket; which is opposite of what I typically find in the region.
Recently I dug some phosphorescent fluorite crystals, I don’t have a good UV source except for a cheapo LED lamp I bought from China, but I decided to give this a try. There was enough UV that some of the crystals did phosphoresce a blue/greenish color. I’ve never checked out any of my crystals this way so it was awesome to see the illumination continue for well over a minute. I wonder what a more powerful lamp would do?
I am still experimenting with what quality of the stones allows the phosphorescence. At first I thought that only the more gemmy of the crystals I found phosphoresce, but that isn’t true. Some of the most gemmy crystals do not phosphoresce at all!
Here is an example of a clear gemmy piece of Fluorite I found, it is pretty but does not phosphoresce.
Here are the fluorites phosphorescing. I charged them up with a cheapo UV LED lamp, then turned off the lamp and opened the exposure for 5 seconds in the pitch dark. They were a bit more green than this picture shows. They stayed illuminated for several minutes.
Here are some of the petrified wood pieces that I picked up at my friend’s property in Northeastern Douglas County in Colorado this last weekend. The wood in Douglas County dates back up to 55 million years ago. To put this in perspective, the last phase of tectonic activity formed Rocky Mountains around 80-55 million years ago; so these are wood from the forests on the craggy, new Rocky Mountains! Interestingly, much more recently in time (about 100ish years ago), wood forested from the Palmer Divide was used to build cities like Denver. Forests have covered the land here in east-central Colorado for a long time!
So how did I find it, well, I just walked around and picked it up off of the ground, for the most part. It tended to be all together, so once I found something on the surface, I could search around that area and find more. I also tried digging some, and there was more under the surface as well.
Still searching for the intact logs on this property like was found recently at the Cherokee Ranch in central Douglas County! Anyone have any suggestions for lapidary treatment of petrified wood?
What a great find!
This was one of the larger pieces I brought home. About 16 to 18 inches long.
These red and orange pieces are just beautiful!
Some of the pile, you can see the variety of color and agatized wood.
I especially liked the color on this piece.
This has the neat bark and also a view into the beautiful golden yellow wood.
I often get asked “How do you find crystals you have posted?”. Which techniques to use is a very subjective question, but certainly there are standard ways of prospecting for pegmatite crystals here in Colorado. I will try to cover some of the techniques I use in this blog post.
UPDATE: I have posted another blog post showing examples of these techniques here.
It has taken me years of prospecting, tons of reading, and networking with other prospectors and rock clubs to figure out what I’ve learned to find crystals so far, so I’m hoping that if you are new to this hobby this article can help expedite the learning curve and take away some frustration…i.e. not coming home empty handed as often! Note that I sometimes STILL come home with nothing to show (and I keep even the littlest crystals)…I think of it like fishing, sometimes the fish simply aren’t biting. My other hope is that folks having successful techniques can share their wisdom so I and others can continue to learn (the comments on this article is a great place, hint hint !!!). Note I am self-taught and have no formal geology schooling or experience, so my descriptions in this article may be scientifically inaccurate; the goal of this article is not to explain the science as much as for tips to helping you learn to find crystals! Of course the science is helpful and very interesting, if you have anything to share or correct (or have further questions), please leave comments, I would love to hear your techniques, opinions and knowledge on the subject!
Hitting a crystal pocket gives you a tremendous high! This was my first crystal pocket!
How to Find Crystals
There are three standard ways I prospect when searching for crystals; I may use only one way on any given day, or may use all three:
Searching the tailing piles of other digs
Finding float and following it
Digging in the source pegmatite
Prospecting Tailing Piles
When I’m prospecting I always check out old and new digs. There are several reasons for this–to learn what the other prospector was into when (presumably) they find crystals themselves, to perhaps continue where the previous prospector didn’t go, and to search through their tailings to ensure the weather didn’t reveal something that was missed or discarded!
Mount Antero double terminated Phenakite my son found laying on the surface, would have been great to have more of that aquamarine attached!
If the prospector was into a pocket or seam of crystals, they may have had mud or iron coatings on the crystals so the prospector tossed aside because they couldn’t see the sides or simply missed it…it happens, I’ve gone back to my digs before and found incredible crystals that I somehow missed! After a good rain or season of snow Mother Nature may help to reveal crystals that were left behind! This is the easiest form of prospecting. I also find that some prospectors are not interested in “boring” or imperfect crystals; another person’s trash may be my treasure! I have found many great crystals by searching the tailings of previous digs!
Tips include
to find crystals it helps moving around the pile to get a reflection of sunlight from a flat shiny surface of a crystal…you should train your eyes to focus on any flat sided rock
getting down closer to the ground for a different perspective; I find many crystals this way that I missed standing up
look for color, some crystals are coated with iron-based minerals and may look rusty
poking around the sides of the hole to see if the prior prospector left part of the pocket
looking for float from the pocket (talked about further below)
dig through the tailings to see if other crystals are slightly buried
Finally there is a lot to learn from studying what others were into. This is how I’ve done much of my learning. What did the rocks they were pulling out look like (note to self, keep an eye out for these signs in my holes)? Are there other digs along the hillside along the same “zone” that I should also check out? What did the other person see that kept them digging? The bigger the prospector’s hole the more likely they found something good (otherwise that is a lot of effort for nothing), so explore those big holes/trenches for sure!
This Milky Quartz and Fluorite plate was found discarded by the original miner on the dumps, cleaned up it is awesome, good enough for me! Just wish I could find the other material which made this trash in comparison!
These Fluorites were covered in pocket mud and then again in dirt. Always examine “dirt balls” !!! Needs some more cleaning, but examples of what you can find in the dumps. Fluorite and other crystals are heavier than other rocks, so pay attention to the weight of the rocks you are extracting!
Prospecting Float
First of all, what is float? It took me a while to get my head around this concept. My definition of float is simply any rocks or crystals that have weathered out of their original location — in other words Mother Nature has moved them via some process over time.
What could have moved the crystals? Glaciers, wind, rain, etc. Glacial movement is pretty easy to spot on the crystals, because they are broken, cleaved and/or have rounded corners like they’ve been in a rock tumbler. These crystals have been potentially moved long distances and there may be no correlation in where the crystals are located to where they originated from–in other words they may be randomly displaced and you may not find other related crystals around them. However I have found several times that pockets were moved (relatively) together by glaciers and there are concentrations of crystals that are completely worn in a somewhat small of an area.
Float coated smoky and milky quartz crystals found in a 10 foot diameter area about 6 inches under the ground. The left smoky is ~10 cm.
Wind and water (and ancient glaciers too) are common forces that move crystals from their original location in the seams/pockets they were grown in. Over the hundreds of millions of years (or perhaps just thousands, or even last month’s torrential rains?) the land has been eroded and the original locations of the crystals may have been partially or completely eroded away. If on a hill, the crystals are likely displaced downhill as they are eroded out of their original pocket. If on a flat area, crystals can disperse radially away from the pocket (which may at one time long ago been above you).
One misconception that I originally had about float was that the crystals would be laying atop the ground easy for the prospector to see. It took me a while to realize that float can be (and often is) buried. The layer of topsoil / organic matter is a recent addition to the ground (decomposed plants, trees, etc) in the perspective of geologic time. Most often I’ve discovered float that is buried in the boundary between the top soil and the granite gravel layers which can be visible or buried many feet deep. Note that with the hundred plus years of prospecting occurring in popular areas, it is very unlikely you’ll find crystals on the surface; but there is still plenty of float to be discovered!
Now that we’ve reviewed what float is in theory, how does one utilize this float concept to actually find crystals? When I find good signs on the ground I dig test holes (more about what are good signs in a minute). I try to dig deep enough so I’m at (or below) the boundary layer between the topsoil/organic matter and the gravel–the steeper the hills the likely this layer will be more shallow. I will also dig about a foot or sometimes two deeper to see if what I’m seeing at the surface continues in situ underground–signs of a pegmatite outcropping.
As I continue to explore the source of the float, I will dig an area of several feet in diameter, left and right, up and downhill. If I continue to find signs, then I will follow those signs in whatever direction they lead me, which typically trends uphill. The hope is that this investigation leads you to the originating crystal pocket or seam still in the pegmatite rock!
If there are no signs on the surface but the area in general looks or “feels” good, or if I’m feeling lucky, I dig test holes in best-guess locations and if I find nothing interesting within a 2-3 foot diameter, I move on to another spot.
I have also seen videos of folks using dowsing rods–the concept is they loosely hold L shaped rods in each hand and as they walk over an area with a crystal the rods will move. I keep thinking I should try this but I have no experience nor have done any research on this technique yet. Chime up in the comments if you’ve had success with this method!
A float dig. I was following signs up the hill (probably 10 feet here) digging only about 3-7 inches deep. Notice the pile of dirt on the right, this makes it ultra fast to fill in the hole once I’m done…literally 2 minutes. I often backfill the hole as I’m following the float. Notice the rocks on the surface above my digging, these are what you want to see, but in this case they are likely from another dig up the hill as they are not partially buried like Mother Nature would do.
What are good signs to follow? What do you look for on the surface to start digging there? How long do you follow the trail of good signs when they are not panning out? Well, that IS the trick, these are all the million dollar questions of prospecting! I’m still perfecting this myself and likely will be forever, but for now my answer is many things. Here is where joining up with a Crystal Club or digging with other prospectors is very helpful. I have found that even though I’ve read a ton on the topic and talked to many experienced prospectors, I didn’t really “get it” until I’ve gone and and moved some rock and dirt–experienced it; sometimes it even takes many times before what I’ve read or been told clicks. That said, however, I’ll try to give you some tips and rules of thumb based on what I look for.
You are looking for the following, above and/or below the surface as float or in situ:
Anything with flat sides. Train your eyes to see flat surfaces; having flat surfaces means there was enough room for the rocks to start to crystalize which is evidence of a crack, seam or pocket in the host rock. Finding flat sided rocks is integral in the hunt for crystals.
Quartz. Pegmatites are partially composed of quartz, so you are looking for chunks of quartz either by themselves or mixed with Microcline / Feldspar.
Microcline. Like quartz above, microcline or amazonite is a good sign.
Graphic Granite. Granite by definition is composed of small crystals of quartz and feldspar. Pegmatite is when the crystal sizes get to a certain size. Graphic granite / pegmatite is where these crystals get bigger TOGETHER. Often in just one rock sample you’ll see the crystal size increase from one side to the other! (see image below). This sometimes means you are getting closer to where the crystals can grow better (i.e. a pocket).
Combinations of above. This means that all the right ingredients of a pegmatite seam are floating out of somewhere.
Crystals. If you’re finding whole crystals or multiple sides, well, you’re there! Congratulations!
Here are some good examples of graphic granite from one of my digs. Notice the quartz crystals getting bigger in size and consistent through the rocks. Click the image for a larger picture with more detail.
These pieces of quartz are great signs with many sides–but none are totally faceted which tells me they came out of massive granite. Also notice the microcline. Follow these!
Example of a good mix of quartz on feldspar, almost (but not quite) starting to look like a plate of quartz crystals. The upper quartz has a several flat sides! This chunk definitely kept me on the hunt!
One other technique I use digging float uphill is when pulling out quartz or microcline chunks I leave them on top of my tailings pile close to the spot I found them. If I’m not finding the source of the float or lose track of the good signs (or when I take a water break), then I’ll often step back, take a break and review what I’m finding from a distance (which is possible because I left my findings consistently in sight on top of the tailings). This technique will let me analyze my current prospecting situation from a different perspective. While analyzing the rocks as I have dug up the hill, I will also analyze the surrounding hillside for clues like other digs, surface rock, contour, etc. Sometimes I get overzealous in my digging and forget this simple step-back-and-analyze step which can be really helpful in minimizing the search for the source of the float!
Another way to find crystals using the “float technique” is to start at someone else’s dig and start to explore around (if a flat area) and downhill of that prospect/hole. It’s likely that there is float around or below that pocket that someone else has done all the hard work and located for you! Many times the crystals are really nice and have just rolled down the hill a little bit!!! The original prospector was only interested in the pocket material and left all the easy float finding to someone else! I’ve found some really nice crystals using this technique!
Prospecting Pegmatites
Of course, the best place to dig is in crystal pockets. This is where the crystals will likely be the best quality and most plentiful (but not always, ask any experienced prospector and they will tell you stories of hours/days of work in fabulous looking pockets with junk, crushed or no crystals). Whether you happen upon a seam or pocket in the pegmatite using float prospecting techniques, or you find the peg right away and dive in, this is the goal of prospecting–to hit the mother lode!
First, a little bit of theory from what I have discovered in the field and also from reading and talking to other prospectors. I think of pegmatites as basically a lava flow of harder rock that when forming had the right (and larger) concentrations of minerals we are searching for. Because it is a flow, it often will be long and extend across or into the hillside and will often be somewhat straight. This is helpful to know as you often can follow the pegmatite as it trends in a somewhat straight direction across the hillside.
If the conditions were right at that instant of time millions and millions of years ago, you have highly mineralized fluid that was flowing through the cracks in the rocks. If there was room in the host rock’s cracks then it would give the fluid a chance to crystalize in that “open space” in the rocks. Because we’re talking about an extended “flow”, the pegmatite can open up (i.e. crystals!), then pinch out, and follow that pattern again and again along faults or cracks over its length. You sometimes see this play out when following the pegmatite getting pocket after pocket along the length of the peg! This is something to remember as a previous prospector may have found a great pocket but didn’t finish it or follow it as it opened up into even a larger pocket along the length of the original flow!
The great Blue Cap Productions video on Rhodochrosite at the Sweet Home Mine in Alma Colorado details that pockets were often found at the intersection of faults. I have found this to be true in some cases with pegmatites pockets I’ve found, as two pegmatites intersected there was a pocket. Additionally, Joe Dorris of Glacial Peak Mining has documented that when the pegs bend they often form pockets (which were eddies during the liquid phase?). This is also something I’ve experienced and definitely keep an eye out for.
Pegmatite is currently often surrounded by gravel or dirt. Over geologic time, the surrounding rock may have decomposed into gravel while the harder, more mineralized material is still in place. So once you are upon the pegmatite you’ll likely know its boundaries by gravel. Knowing this, I don’t spend much time when digging test holes if there is just gravel, but if there are chunks of peg, quartz or microcline then I continue as I may be digging into a pegmatite; and if I was into the peg and then enter into just gravel, I change my direction as I likely have found a border of the peg. When finding bigger chunks of rock, ensure they are pegmatite and not just solid granite. You won’t find many crystals if you are not in the pegmatite!
Note that have seen instances where all the surrounding rock is completely gone leaving just a trail of crystals in the gravel or dirt! So again none of these techniques is absolute each and every time!
I categorize the peg in a couple of ways, as described above (chunks) and also as solid masses (this digging takes the most effort). Sometimes I get into a peg that is still holding together as more massive rock and there is a seam sandwiched between top and bottom plates of granite. In that seam, especially when it has the opportunity to widen, I sometimes find small pockets of crystals. Following these openings the trail of crystals sometimes dives deeper; and that is where things can get interesting as you may be into a pocket. Note that these chunks of pegmatite can be quite large and heavy, requiring pry bars and even chisels and hand sledge hammers to extract, so ensure you are employing safe leverage and lifting techniques (a hurt back doesn’t allow one to dig for many crystals) and always wear eye protection! In these cases I follow the peg in all directions as the crack/seam may be rather long and wide but not very thick, but eventually it could widen and form a pocket. Here is a video example of this (these are HD video, so change the resolution if you have the bandwidth!).
So these are the techniques that I am currently using to find crystals. I am fairly successful in finding some crystals, but finding the great crystals or pockets is still somewhat elusive to me! My thought is it’s all about moving dirt and rock to maximize the chance of getting lucky. Comparing it to the lottery, you have to play to win! Regardless, employing these techniques has brought me success and hopefully will aid in your success too! As stated before, I would love to hear your techniques and ideas in the comments or by emailing me; I’m looking for any ways to improve!
Here are some videos showing me finding crystals out of a pegmatite pockets or seams. Pay attention to what is surrounding the areas with crystals as that is what you will be targeting when you dig! Additionally, I have accumulated a playlist of people extracting crystals from around the world, you’ll want to check it out!
For more articles on my prospecting adventures click here.
You should also check out the other blogs I follow with great information about prospecting in Colorado:
I was able to head up to the hills again, twice in one weekend (albeit a long weekend) for about 4 hours on my way home from a camping trip, decided to prospect a little in a new area. I found some ground that looked promising, and out came some nice peg. I dug the peg for a while with no luck at all, but was persistent because it was too late to prospect out new ground for the day.
The smoky quartz crystals I found over about 45 minutes of carefully digging through the pegmatite.
Right before I gave up for the day I hit into a half baked clear quartz crystal; with no point and completely fractured; but with the flat sides and about 3 inch length I got renewed interest in this peg. I have found that clear quartz when digging for smokies sometimes is a sign that smoky quartz is nearby. I carefully dug for about 10 minutes more and a small gemmy smoky quartz crystal popped out.
Gemmy smoky quartz that started my renewed interest in this peg
It has been a while since I hit a small pocket, I actually like harvesting small crystals as it presents a challenge of being careful and clean in the hole. Many prospectors have no interest in anything of this size, but to me a crystal is a crystal regardless of size. 🙂 It is easy for the small crystals to be covered in dirt and swept away, so I had fun for the next 45 minutes or so meticulously pulling out tiny smoky quartz crystals!
I love how this crystal is irradiated only for part of the crystal, the rest is clear!
In one section of the peg there was some nice micro plates of quartz with crystals, but it finished as soon as it started and was tough digging as it was surrounded by very hard peg (I had to use a chisel and hammer and attack it around the pocket). I was able to pull out many gemmy smoky quartz before calling it a day. The peg continued on, so I suspect I can go back another day and continue to collect ultra small crystals. Some of these crystals were the smallest I’ve ever dug; so I was very happy with the day!
Neat tabby that was totally gemmy!
This one was odd; neat growth at the bottom of the tiny pocket!
The smallest plate of smoky quartz I have ever found. Way smaller than the tip of my pinkie finger.
A piece of microcline crystal with a small seam of tiny smoky quartz
Was able to break away from work so I took a vacation day and went up to Devil’s Head digging this last Friday. Been rough to get up there this year due to a busy schedule, but it was nice to be back out in the forest again.
I had a plan for this day–which I had been pondering upon over the last month while planning this trip. First thing I wanted to prospect an area that I remember looking promising a couple of years ago and if that didn’t pan out I wanted to dig some float on a very old dig I found that seemed pretty productive to the original prospector. If I got skunked with both parts of the plan I had a third option that was within a mile.
I stopped several times during my prospecting and checked out what looked to be good ground in many places. There was peg showing on the surface–both quartz, feldspar and combos–but the quartz was very striated, fractured and had no flat faces at all. I found many places along this steep hillside with the same situation, even though there was a lot of “good looking” signs on the surface. I ended up finding one rough point about the diameter of a nickel in one spot, but nothing otherwise. The hill was *very* steep and after nearly 4 hours I got tired of all the climbing and precarious hiking so I decided to give up on that area.
Stash of crystals I brought home from today’s “float dig”, all rinsed with water, none cleaned in chemical yet.
My second stop was about 1/2 mile away and was a old dig that someone obviously had success with as they had excavated a trench about 50 foot in length as they followed the pegmatite dike across the hillside. I could tell the dig was really old because the trench had naturally filled in most of the way and was looking pretty filled in. I believe this is why the Forest Service is okay with leaving holes unreclaimed as over time they naturally fill back in, although I still believe to fill in my holes as it takes a long time for nature to do it; and holes are simply an eyesore in our forest and potentially dangerous to animals!
My goal at this location was to see if I could find float or perpendicular seams coming out of the peg with some nice sized crystals (given the dig was fairly large). In other spots I have found my best crystals not in or under the pegmatite dike but rather coming out perpendicular to it in many spots in smaller peg seams. I also figured as I got into the old diggings I could possible see what the person was into–I always like to analyze others’ digs as this is a primary way I learn!
I started digging about 4-6 feet downhill of the old trench about 2-4 feet wide and a couple of feet deep. It was hard to tell if I was just digging in tailings or actual virgin ground below the trench, but soon I started finding crystal parts which narrowed my focus. Quickly I zoned in upon a small seam with microcline and smoky quartz crystals. Some were nice and I kept them; but most were only partially euhedral which was a sign of a smaller, tighter seam–even though some of the crystal parts were 5-7 inches long!
The crystals were organized to make me think this was not float (i.e. eroded crystals that eroded and rolled downhill from the pocket) as evidence of microcline and crystals next to each other and some red stained dirt. They definitely were in loose dirt and not harder rock. I followed this seam at a angle of about 30 degrees from straight downhill (I was on a very steep hill) for about 25-30 feet until it disappeared. The further downhill I went the smaller the crystals shards were, the less smoky in color and less frequent. The last 20 feet or so didn’t have anything worth keeping.
A nice euhedral microcline (right), microcline with mica, triple quartz cluster and double terminated smoky quartz were some of the nicer finds of the day.
As I made my way into the old trench from below I started hitting larger masses of pegmatite (like three feet deep), this was the original peg that the prospector followed across the hillside. The digger left many crystals along the bottom of that seam and had obviously found a crack in the peg that had crystals, which is where I often also find my crystals. The unfortunate thing was that the digger obviously used metal tools in this seam and most of the crystals he left attached to the bottom of that seam were damaged on their points. Obviously the digger was finding nice crystals because they didn’t care about the nice 2-3 inch ones they were damaging all along the bottom of the small pocket/seam. Moral of that story, don’t use metal tools in your pockets and take your time, unless you don’t care about the “little guys”!
Nice sized crystals with damage due to carelessness of the previous digger using metal tools in the pocket. You can guage the size by the soda can ring on the old table.
I dug until the sun was setting (beautiful sunset) and it started to sprinkle, since I had a heck of a hike (about a mile with some steep hills) back to the car I didn’t want to wait and have it get dark. As always, had a blast being out in the forest prospecting and was able to prove that–whether it is float or a perpendicular seam–there are sometimes crystals left behind by other prospectors and available if you put in the work from previous digs. This is definitely easier than prospecting good ground signs and striking into virgin ground, which likely will improve the chances of finding crystals quickly?
These were some of the smoky quartz that would fall out of the pocket when I shook the tree roots. Some of the bigger quartz from the pocket
It has been a while since I’ve been up in the hills, but recently I _finally_ had a free day and I was able to hit the hills and prospect for some crystals. This year has been somewhat slow for me so far, I’ve ventured up to dig for Amazonite and/or Smoky Quartz two times before and I had found just a small crystal or two in those days. I also was prospecting way away from my normal places too, but you never know until you check it out!
This last outing, however, I went back to a spot I had luck with in years past as I wanted to dig down deeper. I’ve been told by numerous folks that digging deeper around a seam or small pocket in the pegmatite often yields huge rewards, so I decided this was the day to expend some energy and find out. I arrived at 6am and it was nice and cool so I started to trench out diagonally from where I had luck before. I went about 3-4 feet deep working through some very hard rock to find nothing but gravel on the other side of the pegmatite. I continued elongating the trench and was able to find some peg that was looking okay but it was producing nothing but hard work. After 5 hours of digging I decided that down was not the source at this point and started to fill in the large hole.
One thing I also wanted to try at this spot was to follow the peg past where it appeared to pinch out when I was onto crystals in years past, so I went about 10-15 feet beyond in the general direction of the seam and started another probe hole. Immediately I was pulling quartz chunks out but none with euhedral sides; they appeared to be float as they were in the deep organic matter. I went down about 3 feet and finally started to hit the pegmatite! It continued and I was happy to see it! I trenched it for a while perpendicular to the peg and was pulling crystals out in the past, some some graphic peg appeared but nothing at all with facets. The peg was rather thin at this point and nothing was in the gravel below. I ended up with my trench into the roots of a tree and since there were no positive signs I decided to give the tree a break and not damage any of the roots. So I filled in that hole and took a break as that was another 2 hours of hard work!
This was the other quartz crystal in the center of the pocket. Neat double terminated crystal that is completely gemmy inside! Love that root beer smoky color!
Heart of the pocket, double terminated crystal all cleaned up.
While eating lunch and taking a break, I noticed a rock that was on the other side of my tree that appeared to be buried pretty deep. After eating I tried to pull it out but it wouldn’t give. Interesting that on its side there appeared to be some quartz chunks so I got out the pick and dug it out. It definitely had better shape than any of the peg I was in before lunch, so I started to dig around it. The next rock had some green and I knew I was in the right spot. In just a little while I was in the start of a seam with some nice smaller partially euhedral quartz and amazonite shards. The peg was definitely different than the one I dug in previously so I continued uphill.
About a foot further down and up hill the peg opened up a little and in that opening I started to get more green shards of microcline and a larger quartz chunks. One of the first quartz pieces I found was what looked like a tip of a larger crystal. I see this all the time and I realized that I likely had a really big crystal in store up hill! It was nearly at the other side of the seam/pocket, so it had fallen downhill several feet in the seam which was very interesting…Upon hitting a stump of an old burnt out tree I then discovered the small pocket. Unfortunately my phone died and I didn’t have my regular camera so I can’t share any pictures of the digs, but as I dug through the large roots crystals started to appear. The microcline was light amazonite and some crystals fit into the palm of my hand. Upon shaking the roots crystals would fall into my hole below! It was a quite fun pocket but it receded as quickly as it opened up. Still I was able to get some good sized crystals and amazonite including a couple double terminated (one healed) smoky quartz. I was dead tired by after 5pm (almost 12 hours digging) so I filled in all the holes completely and headed home. Who knows, there could be more there (maybe dig down like the experts say?), I’ll have to check it out again some other time.
Uncleaned, straight from the Earth, some light colored Amazonite crystals
Soaked for a week in a hot oxalic acid bath, the powder blue color is nice–but no where as nice as the green further south.
As in nearly EVERY pocket I dig, I find a broken tip. This time, I was digging up hill and found the tip first. I knew that was a great sign and that I’d find its adjoining large crystal which made an exciting dig!
Smoky quartz cluster that came out of the center of the pocket. Uncleaned.
Here’s your first source for Crystal TV! All action with none of the drama!
I’m not sure how many of you like to watch excavations of crystals from the ground; but as an avid rockhound / picker I love to see crystals unearthed!!! I also learn from seeing it done, so I have been seeking out likeminded folks doing likeminded things!
Here is my YouTube playlist of videos of folks digging crystals from the ground including my own videos! If you have video(s) that should be included make sure you let me know!
