Sedimentary / Mineral (Silica)
Jasper (Iron-stained Chalcedony)
SiO2 with Fe2O3 (Iron Oxide) impurities
Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown, Luster: Waxy to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.58-2.91
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown, Luster: Waxy to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Hexagonal), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.58-2.91
Formation & geological history
Formed through the infiltration of silica-rich fluids into cracks or cavities in volcanic or sedimentary rocks. The reddish color comes from iron minerals (hematite or goethite) deposited during the silification process over millions of years.
Uses & applications
Primarily used as a gemstone for jewelry (cabochons), ornamental carvings, stone seals, and as an industrial abrasive in some cases. It is also popular in 'rock tumbling' and lapidary arts.
Geological facts
Jasper is an opaque variety of chalcedony. Historically, it was a favorite gem in the ancient world; its name can be traced back to Arabic, Persian, Greek, and Latin languages. It is often referred to as the 'Supreme Nurturer' in metaphysical circles.
Field identification & locations
Identification in the field: Look for its high hardness (it will scratch glass), opaque nature, and smooth, waxy surface on river-worn or weathered edges. Common locations: Brazil, India, Madagascar, and the western United States. Collectors should look for unique banding or patterns.
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