Identification

Azurite Identification Sheet

The deep azure-blue copper carbonate, malachite's constant companion, confirmed by its light blue streak and acid reaction.

Identification

Topaz Identification Sheet

The Mohs 8 reference mineral: hard enough to scratch quartz, with perfect basal cleavage and striated prismatic crystals.

Identification

Rhodochrosite Identification Sheet

Colorado's rose-pink state mineral: a manganese carbonate identified by color, low hardness, rhombohedral cleavage, and a warm-acid react…

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…

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