sedimentary
Jasper (or Chert Pebble)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectMohs hardness of 6.5-7, dull to waxy luster, conchoidal fracture, opaque reddish-brown to tan color with dark inclusions.
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Physical properties
Mohs hardness of 6.5-7, dull to waxy luster, conchoidal fracture, opaque reddish-brown to tan color with dark inclusions.
Formation & geological history
Forms via silica precipitation from groundwater or hydrothermal fluids in sedimentary or volcanic environments, often rounded by water erosion.
Uses & applications
Commonly used for lapidary work, cabochons, tumbled decorative stones, and jewelry.
Geological facts
Jasper has been used by humans since antiquity for ornamental seals, amulets, and prehistoric tools due to its toughness.
Field identification & locations
Identified by hardness (scratches glass), smooth texture, opaque opacity, and mottled earthy coloration.
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