sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish-red, Luster: Vitreous to dull, Crystal structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture)
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Brick red to brownish-red, Luster: Vitreous to dull, Crystal structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture)
Formation & geological history
Formed when fine particulate matter, often ash or sediment, is cemented by silica during low-temperature hydrothermal processes or as a result of sedimentation in iron-rich environments. The red color is derived from iron oxide (hematite) inclusions.
Uses & applications
Used extensively in jewelry for cabochons and beads, as a decorative stone for ornaments and vases, and historically as a tool stone for its durability and sharp edges.
Geological facts
Red Jasper has been used since antiquity; it was known as the 'stone of endurance' in ancient cultures and was often used in amulets and protective seals. It is a dense variety of chalcedony.
Field identification & locations
Identify in the field by its opaque brick-red color, extreme hardness (it will scratch glass), and smooth, waxy fracture surfaces. Commonly found in river beds, deserts, and volcanic regions worldwide, including the USA, Brazil, and India.
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