Identification Selenite (Gypsum) Identification Sheet A very soft sulfate you can scratch with a fingernail, forming clear bladed crystals, satin spar, and desert roses.
Identification Malachite Identification Sheet A bright green copper carbonate recognized by its color, concentric banding, botryoidal habit, and effervescence in acid.
Identification Onyx Identification Sheet A banded chalcedony with a parallel-layered structure, a hardness that outlasts most imposters, and — in this particular library — a name…
