Rock Identifier
Jasper (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — mineral
mineral

Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown, yellow, orange-brown; Luster: Waxy to sub-vitreous; Crystal Structure: Hexagonal (microcrystalline/cryptocrystalline); Cleavage: None, exhibits conchoidal fracture; Specific Gravity: 2.58-2.91.

Hardness
6
Color
Reddish-brown, yellow, orange-brown
Luster
Waxy to sub-vitreous
Identified More mineral
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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown, yellow, orange-brown; Luster: Waxy to sub-vitreous; Crystal Structure: Hexagonal (microcrystalline/cryptocrystalline); Cleavage: None, exhibits conchoidal fracture; Specific Gravity: 2.58-2.91.

Formation & geological history

Forms as a secondary mineral during the precipitation of silica in volcanic ash or hydrothermal veins, often incorporating iron oxide impurities that impart reddish-brown tones.

Uses & applications

Used widely in lapidary arts for cabochons, beads, ornamental carvings, tumbled decorative stones, and historical seals or amulets.

Geological facts

Jasper has been used as a gemstone since antiquity and is mentioned in ancient Greek, Roman, and Biblical texts as a popular material for engraved gems.

Field identification & locations

Identified in the field by its hardness (scratches glass, cannot be scratched by a steel blade), dull to waxy luster, opaque nature, smooth conchoidal fracture, and brownish-red color. Commonly found in gravel beds, stream deposits, and volcanic regions worldwide.