sedimentary
Red Jasper (River Polished Quartzite)
Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) impurities
Hardness: 6.5 - 7 on Mohs scale; Color: Reddish-brown, terracotta; Luster: Waxy to dull (sub-vitreous); Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58 - 2.91
- Hardness
- 6
- Color
- Reddish-brown, terracotta
- Luster
- Waxy to dull (sub-vitreous)
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Physical properties
Hardness: 6.5 - 7 on Mohs scale; Color: Reddish-brown, terracotta; Luster: Waxy to dull (sub-vitreous); Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58 - 2.91
Formation & geological history
Formed from the deposition of silica-rich fluids in volcanic ash or sedimentary beds. The red color comes from high concentrations of iron oxide. This specimen shows signs of mechanical weathering (rounding) likely from river or glacial movement over thousands of years.
Uses & applications
Used primarily in lapidary work for cabochons, beads, and pocket stones. Also used as decorative gravel or in 'metaphysical' retail as a grounding stone.
Geological facts
Jasper was a favorite gem in the ancient world; its name can be traced back in Arabic, Persian, Greek, and Latin. It is an opaque variety of chalcedony that contains up to 20% foreign materials which determine its color.
Field identification & locations
Identify by its opacity (it does not transmit light even on thin edges), its smooth rounded texture from water-tumbling, and its inability to be scratched by a steel knife. Commonly found in riverbeds and gravel pits worldwide.
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