mineral

Smoky Quartz with Amethyst

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: Brownish-grey to black (smoky) and violet/purple (amethyst). Luster: Vitreous (glassy). Crystal structure: Trigonal/Hexagonal. Cleavage: Indistinct/Conchoidal fracture. Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Brownish-grey to black (smoky) and violet/purple (amethyst)
Luster: Vitreous (glassy)

Identified April 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous environments (pegmatites) or hydrothermal veins via crystallization from silica-rich fluids. The 'smoky' color comes from natural gamma irradiation and trace aluminum, while the 'amethyst' color comes from iron impurities.

Uses & applications

Primarily used as a collector specimen, in lapidary work for jewelry, and occasionally in metaphysical or decorative interiors.

Geological facts

Large clusters containing both smoky and purple zones are rare and highly sought after by collectors. Smoky quartz is the national gem of Scotland, where it is known as Cairngorm quartz.

Field identification & locations

Identify in the field by its distinct 6-sided hexagonal prism shape and pointed terminations. It is commonly found in mountainous regions like the Alps, Brazil, Madagascar, and various US states like Colorado and Arkansas.