Where is Smoky Quartz found?
SiO2 (Smoky Quartz variety of Quartz)
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Open the appSmoky Quartz occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Smoky Quartz
Brazil
Minas Gerais is a major source, producing large, high-quality crystals.
Switzerland
The Swiss Alps are famous for producing fine, often large, smoky quartz crystals from alpine-type fissures.
United States
Notable localities include Colorado (Pikes Peak region), Maine, North Carolina, and Arkansas.
Scotland
The Cairngorm Mountains are historically significant for producing dark smoky quartz, known as Cairngorm.
Madagascar
Produces good quality smoky quartz, often associated with other pegmatite minerals.
Collecting tips
- Look in Pegmatites and Hydrothermal Veins. Smoky quartz is frequently found in granitic pegmatites, which are coarse-grained igneous rocks, and in hydrothermal veins, where hot, mineral-rich fluids have deposited minerals in cracks and fissures.
- Check Alpine-Type Fissures. In mountainous regions, particularly those with granitic or gneissic bedrock, look for smoky quartz in alpine-type fissures, which are often lined with well-formed crystals.
- Examine Alluvial Deposits. Due to its hardness and resistance to weathering, smoky quartz can be found in riverbeds and gravel deposits, often as water-worn pebbles or fragments.
- Distinguish from Obsidian. Smoky quartz is crystalline and has a distinct crystal habit (prismatic), while obsidian is amorphous volcanic glass and lacks crystal structure. Smoky quartz will also scratch glass, whereas obsidian will not always.
- Distinguish from Black Tourmaline (Schorl). Schorl typically forms as striated prismatic crystals with a triangular cross-section and has a much more complex chemical composition. Smoky quartz has a hexagonal cross-section and lacks prominent striations on prism faces.
Quick Check
- Color:
- Brownish-gray to black
- Luster:
- Vitreous (glassy)
- Streak:
- White
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