mineral
Quartz (Citrine or Smoky variant)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Pale yellowish-grey; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Pale yellowish-grey
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Pale yellowish-grey; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.
Formation & geological history
Formed in igneous pegmatites or hydrothermal veins. This specimen appears water-worn, suggesting it was found in an alluvial (river or stream) deposit.
Uses & applications
Used in electronics (piezoelectric properties), glassmaking, watchmaking, jewelry as semi-precious gemstones, and by mineral collectors.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Citrine, the yellow variety, is extremely rare in nature; most commercial citrine is heat-treated amethyst or smoky quartz.
Field identification & locations
Identify by its ability to scratch glass and lack of cleavage. Look for the characteristic glassy, shell-like fracture pattern. Often found in gravel beds or near granite outcrops.
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Metamorphic
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metamorphic
Gypsum (variety Selenite or Alabaster)
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Mineral
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Mineral/Rock
Granite
Granite (Phaneritic intrusive igneous rock)
igneous