metamorphic
Polished red jasper
Jasper, an opaque microcrystalline variety of quartz/chalcedony (SiO₂), colored mainly by iron oxides
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque brick-red to reddish brown with darker mottling and pale veins; takes a smooth, glassy-to-waxy polish. Microcrystalline quartz, with no visible cleavage and uneven fracture; specific gravity about 2.6.
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Physical properties
Hardness about 6.5–7 Mohs; opaque brick-red to reddish brown with darker mottling and pale veins; takes a smooth, glassy-to-waxy polish. Microcrystalline quartz, with no visible cleavage and uneven fracture; specific gravity about 2.6.
Formation & geological history
Forms as silica-rich sediment or volcanic material becomes silicified, with iron compounds providing the red color; many deposits are Precambrian, though jasper occurs in rocks of many ages.
Uses & applications
Used for beads, cabochons, ornaments, and polished collectible stones; jasper is also used decoratively in carvings and small objects.
Geological facts
Jasper is a trade name for opaque, patterned chalcedony rather than one narrowly defined rock type; its patterns and color vary with impurities and local formation conditions.
Field identification & locations
The rounded shape and high polish indicate a tumbled or otherwise polished specimen. Red color, opacity, and hardness distinguish it from softer red stones; jasper is found worldwide, including India, Australia, Brazil, and the western United States.
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