sedimentary
Fancy Jasper (Ocean Jasper or River Jasper variant)
Silicon Dioxide with inclusions (SiO2)
Hardness: 6.5 to 7 (Mohs scale). Color: Red, green, and cream mottling. Luster: Vitreous to waxy. Structure: Microcrystalline (trigonal system). Specific Gravity: 2.58 to 2.91.
- Hardness
- 6
- Color
- Red, green, and cream mottling
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5 to 7 (Mohs scale). Color: Red, green, and cream mottling. Luster: Vitreous to waxy. Structure: Microcrystalline (trigonal system). Specific Gravity: 2.58 to 2.91.
Formation & geological history
Formed through the infiltration of silica in sedimentary environments or volcanic ash beds. The mottled colors are caused by varying mineral inclusions (iron oxides for reds, chlorite for greens) occurring during different stages of deposition and pressure.
Uses & applications
Primarily used in jewelry (cabochons and beads), decorative carvings, and as a popular meditation stone in metaphysical practices. In industrial history, silica-rich jaspers were used for flint tools.
Geological facts
Jasper is an opaque variety of chalcedony. The name 'Jasper' is derived from the Greek 'iaspis', meaning 'spotted stone.' Many 'Fancy Jasper' specimens are sourced from India or South Africa.
Field identification & locations
Identify in the field by its opacity (it does not transmit light even on thin edges), its smooth conchoidal fracture, and inability to be scratched by a steel pocketknife. Commonly found in riverbeds or within nodes of larger sedimentary rock formations.
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