Red trinitite is technically not a true mineral, because it was not formed through a geologic process. Rather, this brick-red colored...

At first glace, this looks like a classic selenite rosette from the Red River Floodway, Manitoba, Canada. But no, guess again! This...

Tiffany stone is a complex rock composed of opalized fluorite with bands and veins of chalcedony, manganese oxide and bertrandite. The...

Yttrofluorite is a variety of fluorite in which the rare earth element yttrium substitutes for some of the calcium in the fluorite (CaF2)...

Yttrofluorite is a variety of fluorite in which the rare earth element yttrium substitutes for some of the calcium in the fluorite...

Rare green fluorescent botryoidal fluorite from the Fourmile Creek area, near Canon City, Fremont County, Colorado. Fluorite in...

Brightly fluorescent, submillimeter, octahedral crystals of scheelite on matrix; from the Ophir Hill Mine, Tooele, Utah. This specimen...

To mineral collectors, the Sweet Home Mine in Alma, Colorado is best known as a producer of some of the finest rhodochrosite specimens in...

This lovely 2-color fluorescent specimen contains willemite and sphalerite, and is from the Nelly James Mine (also known as Miller...

This beautiful 4-color rock is from the Nelly James Mine (also known as Miller Canyon), in southern Arizona. At its best under short...