sedimentary
Jasper
Microcrystalline Quartz (SiO2) with impurities
Hardness: 6.5-7 on the Mohs scale; Color: Brown, yellow, red, orange, and black dendrites; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- Brown, yellow, red, orange, and black dendrites
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 on the Mohs scale; Color: Brown, yellow, red, orange, and black dendrites; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Formed through the silification of sedimentary or volcanic rocks, where silica-rich fluids precipitate microcrystalline quartz in cavities or fractures, often over millions of years.
Uses & applications
Used in ornamental objects, cabochons for jewelry, carvings, and as a collector's specimen.
Geological facts
Jasper has been used since ancient times for amulets, seals, and tools. The dendritic patterns are often caused by inclusions of iron or manganese oxides.
Field identification & locations
Easily identified by its opaque nature, hardness, waxy luster, and conchoidal fracture. Commonly found in riverbeds, glacial tills, and areas of ancient volcanic or hydrothermal activity.
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