sedimentary
Jasper
Microcrystalline Quartz (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, reddish-brown color due to iron oxide impurities, waxy to dull luster, cryptocrystalline crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.58 to 2.91.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, reddish-brown color due to iron oxide impurities, waxy to dull luster, cryptocrystalline crystal structure, conchoidal fracture with no true cleavage, specific gravity of 2.58 to 2.91.
Formation & geological history
Formed through the silification of sedimentary or volcanic rocks where silica-rich fluids precipitate microcrystalline quartz in pore spaces or fractures, often in hydrothermal environments or marine sediments.
Uses & applications
Used for ornamental objects, cabochons, carved figurines, lapidary arts, and as a semi-precious gemstone.
Geological facts
Jasper has been used since ancient times to create seals, talismans, and jewelry, with references dating back to antiquity across various civilizations including the Greeks, Romans, and Egyptians.
Field identification & locations
Identified by its opaque nature, distinct reddish-brown color, conchoidal fracture, and lack of scratching from a steel blade. Commonly found in riverbeds, mountainous regions, and areas of ancient volcanic or sedimentary activity worldwide.
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