metamorphic
Polished jasper or jasper-rich breccia
Microcrystalline quartz (SiO₂), commonly with iron oxides and other silicates
AI-generated identification · may be incorrectOpaque, polished, dark brown-black with rusty orange and blue-green patches; vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, Mohs hardness about 6.5–7, specific gravity roughly 2.5–2.7.
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Physical properties
Opaque, polished, dark brown-black with rusty orange and blue-green patches; vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, Mohs hardness about 6.5–7, specific gravity roughly 2.5–2.7.
Formation & geological history
Jasper forms when silica-rich groundwater replaces or cements volcanic ash, sediments, or brecciated rock; iron and copper-bearing impurities create the vivid colors. Its exact geological age cannot be determined from the photograph and depends on its locality.
Uses & applications
Commonly cut and tumbled for jewelry, cabochons, ornaments, and collectibles; occasionally used as decorative stone. Small polished pieces generally have modest commercial value.
Geological facts
The blue-green areas may indicate chrysocolla, chlorite, or other mineral inclusions, so a precise variety cannot be confirmed visually. The specimen appears human-polished rather than naturally weathered.
Field identification & locations
Identify by its opaque fine-grained texture, strong polish, hardness, and irregular multicolor pattern; it will not show transparent quartz crystals. Common sources include India, Madagascar, Australia, Brazil, and the western United States.
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