sedimentary
Jasper
Microcrystalline quartz ($SiO_2$)
Hardness: 6.5-7 on the Mohs scale; Colors: Multicolored, red, brown, yellow, green; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline/cryptocrystalline); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.58-2.91
- Hardness
- 6
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 on the Mohs scale; Colors: Multicolored, red, brown, yellow, green; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline/cryptocrystalline); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.58-2.91
Formation & geological history
Formed by the precipitation of silica-rich fluids or volcanic ash in marine or terrestrial environments, often filling cavities in volcanic rocks. Geological age ranges from Precambrian to recent.
Uses & applications
Used for ornamental objects, cabochons, jewelry, carvings, and as a collector's specimen.
Geological facts
Jasper has been used since ancient times to create seals, signet rings, and various ornaments. Its name comes from the ancient Greek word iaspis, meaning 'spotted stone'.
Field identification & locations
Can be identified in the field by its opaque appearance, hardness (scratches glass), and waxy-to-dull luster with varied color patterns. Found worldwide, particularly in regions with historic volcanic or sedimentary activity.
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