sedimentary
Jasper
Microcrystalline Quartz (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, typically brown to red-brown color due to iron oxide impurities, waxy to dull luster, cryptocrystalline structure with no visible crystal faces, conchoidal fracture, and specific gravity around 2.58 to 2.91.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, typically brown to red-brown color due to iron oxide impurities, waxy to dull luster, cryptocrystalline structure with no visible crystal faces, conchoidal fracture, and specific gravity around 2.58 to 2.91.
Formation & geological history
Formed through the accumulation of silica-rich sediments or silica-bearing solutions in marine or volcanic environments, often during the Precambrian and Paleozoic eras, where iron oxides stained the fine-grained quartz matrix.
Uses & applications
Used primarily in lapidary arts, making ornamental carvings, beads, cabochons for jewelry, and as a collectible mineral specimen.
Geological facts
Jasper has been used by ancient civilizations since antiquity for tools, seals, and amulets. Its name means 'spotted or speckled stone' derived from Greek and Semitic languages.
Field identification & locations
Can be identified in the field by its smooth water-worn surface, lack of cleavage, high hardness capable of scratching glass, and earthy reddish-brown tones. Found globally in riverbeds, beaches, and mountainous regions.
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