mineral

Smoky Quartz occurring with Feldspar

Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (KAlSi3O8)

Hardness: 6-7 (Mohs scale); Color: Pale grey, smoky translucent, and off-white/pinkish; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Monoclinic; Cleavage: None (conchoidal fracture).

Hardness: 6-7 (Mohs scale)
Color: Pale grey, smoky translucent, and off-white/pinkish
Luster: Vitreous to greasy

Identified June 7, 2026More mineral →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Pale grey, smoky translucent, and off-white/pinkish; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Monoclinic; Cleavage: None (conchoidal fracture).

Formation & geological history

Formed in igneous pegmatites and hydrothermal veins as silicate-rich fluids cool and crystallize deep within the crust. These specimens are often hundreds of millions of years old.

Uses & applications

Used in gemstone manufacturing, metaphysical jewelry, glassmaking, and as common collector specimens for beginning geologists.

Geological facts

Smoky quartz gets its dark color from natural irradiation of aluminum impurities within the crystal lattice over geological time. It is the national gem of Scotland, where it is known as Cairngorm.

Field identification & locations

Identify in the field by its hardness (scratches glass), lack of cleavage, and translucent 'smoky' appearance compared to opaque minerals. Common in granite-rich mountain ranges like the Rockies or Alps.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic