Smoky Quartz
Variety of quartz
Common · SiO₂
Brown to black quartz coloured by natural irradiation of aluminium-bearing defects in the crystal lattice. The same colour can be produced by irradiating colourless rock crystal, and standard tests cannot tell the two apart. The morion variety is nearly opaque black.
Identity
- Formula
- SiO₂
- Chemical class
- Silicate
- Mineral group
- Agate, Amethyst, Bloodstone, Carnelian, Chalcedony, Citrine, Jasper, Moss Agate, Onyx, Quartz, Rose Quartz, Tiger's Eye
- Also known as
- Cairngorm (Scottish variety), Morion (very dark black variety)
Crystallography
- Crystal system
- Trigonal
- Habits
- Prismatic
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 7
- Density
- 2.65 g/cm³
- Luster
- Vitreous
- Colors
- brown, gray, black, brownish black
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Igneous, Hydrothermal
- Host rocks
- Granite, Schist and gneiss
- Associated minerals
- feldspar, Mica, Tourmaline
- Found in
- Pegmatite deposit
- Geography
- Brazil, Scotland, Switzerland, USA, Madagascar
Classification
- Rarity
- Common
- Gem quality
- Yes
Sources
- Smoky Quartz. Mindat.org (Hudson Institute of Mineralogy).
- Smoky Quartz. Gemdat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Quartz. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Quartz. Mindat.org (Hudson Institute of Mineralogy).
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
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