What it is confused with
Clear quartz irradiated in a laboratory, brown glass, and stones misleadingly sold as "smoky topaz".
Pale gray-brown to near black
Smoky Quartz crystals
Smoky Quartz is silicon dioxide (SiO₂) darkened by natural irradiation of aluminum impurities, pale gray-brown to near black, rated 7 on the Mohs scale. Traditionally, it is associated with settling anxiety and staying present — attributed, not demonstrated.
- Mohs hardness
- 7 scratches window glass
- Crystal system
- Trigonal SiO₂
- Main sources today
- Brazil also Switzerland, Scotland
Properties
Composition
Silicon dioxide (SiO₂) darkened by natural irradiation of aluminum impurities
Hardness (Mohs)
7
Crystal system
Trigonal
Color
Pale gray-brown to near black
Mined in
Brazil, Switzerland, Scotland, Madagascar
Worth knowing
Its color comes from natural radiation acting on aluminum traces over geological time — heat it and the smoke disappears.
History
The national gemstone of Scotland, where it is called cairngorm.
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Buying
Buying Smoky Quartz: fakes, value and treatments
What decides the price
Inexpensive even in large sizes; very dark, nearly black smoky quartz is called morion.
Where it is used
Traditional Scottish dress: cairngorm stones set in kilt pins and in the hilt of the sgian-dubh.
A less familiar fact
Its color comes from natural radiation acting on aluminum impurities, and gentle heating removes it.
Practical
Caring for Smoky Quartz
How to clean it
Warm soapy water. Heat and strong light will fade the smoke.
How to tell it is real
Much commercial smoky quartz is irradiated clear quartz, which is standard practice. Very dark, evenly black material is almost always treated.
How hard is Smoky Quartz?
Smoky quartz resists dust like any quartz, but its color is fragile: the smoke was made by natural radiation, and heat or strong light can bleach it back toward clear.
Smoky Quartz, at 7, is harder than 28 of the other 42 stones here and softer than 9, with 5 level with it.
Traditional associations
Smoky Quartz is traditionally associated with settling anxiety and staying present. Chakra in crystal practice: Root. Element: Earth.
Questions about Smoky Quartz
What is Smoky Quartz made of?
Silicon dioxide (SiO₂) darkened by natural irradiation of aluminum impurities, crystallizing in the trigonal system.
Where does Smoky Quartz come from?
Brazil, Switzerland, Scotland, Madagascar.
Can Smoky Quartz be worn every day?
Yes. It rates 7 on the Mohs scale, and the main thing to watch is heat and strong light, which bleach the smoke.
Cite this page
AstroHot. “Smoky Quartz Crystals: Meaning, Hardness and Origins.” Accessed October 28, 2026. https://astrohot.com/crystals/gemstones/smoky-quartz/
For Wikipedia
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