Fluorite with Quartz

An old time Hill Ledford piece with some interesting attributes. First we notice that two prominant crystals have what appear to be internal cleaves, making the top third of the crystal appear a different color. There are no impact marks or chipping, so this occurred in situ. The right side of the piece has incomplete (interference) growth, with fully terminated stepped faces. Note that several main crystals are interpenetrant. Quartz coats the inner portion of the matrix. Stands perfectly on its own.

Locality: Hill Ledford Mine, Cave-in-Rock, Illinois

Composition: calcium fluoride