mineral
Quartz (Smoky Quartz)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Grayish-brown to smoky black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture.
- Hardness
- 7 on Mohs scale
- Color
- Grayish-brown to smoky black
- Luster
- Vitreous (glassy)
Identified More mineral →
Explore Quartz (Smoky Quartz) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Grayish-brown to smoky black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture.
Formation & geological history
Forms in igneous rocks like granite or in hydrothermal veins. The smoky color is caused by natural irradiation of aluminum-bearing quartz over long geological periods.
Uses & applications
Used in electronics for quartz oscillators, as an abrasive, and popular in jewelry or as metaphysical healing crystals.
Geological facts
Smoky quartz is the national gem of Scotland, where it is often referred to as 'Cairngorm' after the mountains where it is mined.
Field identification & locations
Identify by its ability to scratch glass, lack of cleavage (breaks like glass), and smoky transparency. Commonly found in mountainous regions with granitic bedrock.
More like this
Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Calcite–fluorite mineral specimen with iron-oxide staining
Calcite (CaCO₃), likely fluorite (CaF₂), with possible quartz and iron/manganese oxides
mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Septarian Pebble
Septarian nodule / Concretion
sedimentary