A particularly fine specimen of fluorite, made up of several crystals. One of my favorite minerals!
Locality: Bergmännisch Glück Mine, Frohnau, Annaberg-Buchholz, Erzgebirge, Saxony, Germany
Size: 3 × 4.1 × 3.2 cm (1.2 x 1.6 x 2.3 in.)
Photo: © Wittig-Minerals /e-rocks. com
H/T: www.geologypage.com
@sarahc Do we know what are the nucleation sites for the crystals or is it homogenous?
@SteelFolk @sarahc That actually looks like a single crystal. But that doesn’t really make the answer to your question any easier.
@SteelFolk @sarahc Not so very different. Fluorite can be masses of interpenetrating crystals. But this piece is the result of unrestricted growth from some substrate into a fluid space. It could be a crack, or some kind of geode/cavity. If there is still space once crystallization ends, then you see these accretionary faces preserved. It happens with any mineral. Even pure metals. When the growth conditions allow it, you get crystal growth faces preserved.
@SteelFolk @sarahc I assume that means you can make use of “seed” crystals to influence the accretion pattern? In nature, pure metals are considerably rarer, since most seem to like bonding with Oxygen (always have a date for the crystal party). When they are pure ( like noble metals) the same rules apply.
@SteelFolk @sarahc Wow! That’s pretty freaking advanced. One can only imagine how microgravity will open the door to even more advances. In my head, I see huge L-point rotating induction furnaces “digesting” billets of titanium being shot from lunar magnetic guns. 😁