sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
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), Specific Gravity: 2.6-2.9.
- 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), Specific Gravity: 2.6-2.9.
Formation & geological history
Formed when silica-rich fluids permeate through volcanic ash or sedimentary deposits, picking up iron oxides (hematite) that provide the red color. Typically occurs in veins or as nodules.
Uses & applications
Primarily used for lapidary work, jewelry (cabochons, beads), decorative carvings, and as a popular specimen for rock tumbling and metaphysical collections.
Geological facts
The red color comes from the presence of iron oxide (hematite). It has been used since antiquity in cylinder seals, jewelry, and talismans, and is mentioned in various historical and religious texts.
Field identification & locations
Identify by its opaque nature, smooth conchoidal fracture (often with sharp edges), and hardness that can scratch glass. Common in river beds and desert environments globally; notably found in the USA, Brazil, and India.
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