Sunday, March 18, 2007

Big Purple Rock

This is the big purple rock I got in Tucson. It was sold as Halite, but after some research I think it might be sylvite? It does dissolve in water, and it tastes salty/bitter (don't try this at home kids!) BUT I can find no images like this on the web any where. Both halite and sylvite usually have cubic crystal formations. It is about 14" x 6 " x 4" Very brittle, streaks white, Any ideas out there?

1 comment:

Anonymous said...

Since you don't have a thin section (Or presumably an optical microscope) you have two good options to choose from.

Taste testing is the easiest method. Sylvite will taste bitter, whereas Halite will taste, well... salty.

Another good test is that a knifeblade, when scratched across the surface of halite, will procduce a powder. Sylvite will not produce a powder.