sedimentary (chemically precipitated mineral)
Jasper (likely Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with impurities
Hardness: 6.5–7 on Mohs scale. Color: Multicolored (green, tan, reddish-brown). Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific gravity: 2.58–2.91.
- Hardness
- 6
- Color
- Multicolored (green, tan, reddish-brown)
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5–7 on Mohs scale. Color: Multicolored (green, tan, reddish-brown). Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific gravity: 2.58–2.91.
Formation & geological history
Formed from the precipitation of silica from volcanic fluids or groundwater within sedimentary or volcanic rocks. The distinctive banding and colors are caused by varying mineral inclusions (like iron oxides) deposited during the silica solidification over millions of years.
Uses & applications
Primary use is in lapidary for jewelry, cabochons, and decorative ornamental carvings. It is also a very popular stone for mineral collectors and practitioners of holistic lithotherapy.
Geological facts
Jasper is an opaque variety of chalcedony. The name 'Polychrome Jasper' specifically refers to colorful specimens often found in Madagascar. It was discovered relatively recently (around 2008) while searching for Ocean Jasper.
Field identification & locations
Identify in the field by its opacity (it does not transmit light even on thin edges, unlike agate), smooth conchoidal fracture, and inability to be scratched by a steel knife. Commonly found in Madagascar, Brazil, and the Western United States.
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