For years I've been seeing these at rock and mineral shows; we finally bought a small one to display at home. It wasn't until today that I found at a
Reddit thread the proper designation of the specimen as a "hopper crystal." Here's the explanation re the formation, from
Wolframscience -
When a pool of molten bismuth solidifies it tends to form crystals like [the one above]. What seems to give these crystals
their characteristic "hoppered" shapes is that there is more rapid
growth at the edges of each face than at the center... Hoppering has
not been much studied for scientific purposes, but has been noticed in
many substances, including galena, rose quartz, gold, calcite, salt and
ice.
I bought a beautiful specimen of hopper bismuth at a rock shop in Taos a few years ago. They always remind me of Mayan pyramids.
ReplyDelete@ David: They Remind me of that too! And I was born and raised in Taos NM, thanks for the shout out.
ReplyDeleteHere are some interesting macros of these hoppered crystals:
ReplyDeletehttps://www.behance.net/gallery/25998593/Lab-Grown