Most crystal-digging people know Super Iron Out as a great solution for taking iron oxide staining off of crystals. I typically use SIO as my first cleaning bath for most of my crystals and jump into the acids later if the stains are stubborn. This winter I was cleaning a small micro-quartz cluster in the (cold) garage and was amazed to find my cluster gained another crystal during cleaning.
I must have saturated the small amout of cleaning bath and when the temperature lowered the SIO crystal began to form! The next day it turned from clear to super brittle white; and was falling all over, so I put it back in solution and cleaned more crystals with it!