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!
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!
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!
- 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!
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.
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!
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!
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!
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:
- Rockhounding the Rockies
- Conifer Environmental’s Blog
- Peak to Peak
- Mike Nelson’s CSMS Geology Blog
- Steve Veatch’s Colorado Earth Science
Wish you good fortune as you find crystals!