sedimentary
Green Jasper
Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs), Color: Dark green with brown/gray inclusions, Luster: Vitreous to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal/Trigonal system), Cleavage: None, Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs), Color: Dark green with brown/gray inclusions, Luster: Vitreous to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal/Trigonal system), Cleavage: None, Specific Gravity: 2.58-2.91
Formation & geological history
Forms through the deposition of silica from water-rich environments or the replacement of volcanic ash with silica. It is often found in sedimentary rocks as nodules or vein-filling minerals.
Uses & applications
Primarily used for lapidary purposes, including jewelry (cabochons), ornaments, beads, and as a decorative stone in sculptures.
Geological facts
Jasper has been used as a gemstone since antiquity; green varieties were highly prized in ancient Mesopotamia and Egypt. It is an opaque variety of chalcedony.
Field identification & locations
Identify in the field by its waxy luster, smooth conchoidal fracture, and extreme hardness (it will scratch glass). Commonly found in riverbeds or coastal areas in Oregon, California, and South Africa.
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