sedimentary
Red Jasper
Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3)
Hardness: 6.5-7 (Mohs scale); Color: Bricky opaque red; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91.
- Hardness
- 6
- Color
- Bricky opaque red
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Bricky opaque red; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58-2.91.
Formation & geological history
Formed from silica-rich groundwater or volcanic ash deposits that settle in sedimentary environments. Its red color is derived from high levels of iron oxide (hematite) during the lithification process over millions of years.
Uses & applications
Commonly used for lapidary work, cabochons, bead jewelry, ornamental carvings, and 'worry stones'. It is also an industrial abrasive in some contexts.
Geological facts
Jasper is an opaque variety of chalcedony. It has been a popular gemstone for millennia, appearing in the Breastplate of Aaron in biblical texts and used in ancient Minoan seals on Crete.
Field identification & locations
Identify in the field by its deep red color, opacity (light will not pass through edges), and smooth, waxy texture when wet. Found worldwide, with major deposits in India, Russia, Brazil, France, and the USA (southwest).
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