sedimentary
Green Jasper
Silicon Dioxide (SiO2) with impurities
Hardness: 6.5-7 Mohs, Color: Olive to forest green, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline/Cryptocrystalline, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.6-2.9
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 Mohs, Color: Olive to forest green, Luster: Vitreous to waxy, Crystal Structure: Microcrystalline/Cryptocrystalline, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.6-2.9
Formation & geological history
Formed primarily from the precipitation of silica from groundwater in volcanic or sedimentary environments. Impurities like iron silicates or chlorite provide the green pigmentation. These often appear as river-tumbled stones in alluvial deposits.
Uses & applications
Used in lapidary arts for cabochons, beads, and carvings; historically used for tools due to conchoidal fracturing; popular as a pocket stone or for decorative landscaping.
Geological facts
Jasper is a variety of chalcedony. In ancient times, green jasper was often referred to as 'the rain bringer' and was considered a powerful stone of protection. It is opaque, distinguishing it from translucent green chalcedony or chrysoprase.
Field identification & locations
Identify in the field by its opacity, hardness (will scratch glass), and smooth, waxy texture when wet. Commonly found in riverbeds, beaches, and volcanic regions.
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