sedimentary
Jasper / Agate (Chalcedony)
Silicon dioxide (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, varies in color from red, yellow, brown to translucent, vitreous to waxy luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, specific gravity of 2.58 to 2.64.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, varies in color from red, yellow, brown to translucent, vitreous to waxy luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, specific gravity of 2.58 to 2.64.
Formation & geological history
Formed through the deposition of silica-rich fluids in cavities, fractures, or sedimentary environments, often associated with volcanic rocks or groundwater precipitation over millions of years.
Uses & applications
Used in lapidary arts, ornamental carvings, jewelry, and as collector specimens.
Geological facts
Chalcedony varieties like jasper and agate have been used by humans since Neolithic times to create tools, weapons, seals, and decorative ornaments.
Field identification & locations
Can be identified in the field by its hardness (scratches glass), waxy luster, and conchoidal fracture. Found worldwide in riverbeds, volcanic regions, and sedimentary deposits.
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