metamorphic
Red jasper in a gray host rock (likely jasperized volcanic rock)
Microcrystalline quartz (SiO₂), iron-oxide–colored jasper, in a fine-grained volcanic or sedimentary matrix
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque red-orange and gray, with earthy to vitreous luster and no visible cleavage. The polished/tumbled surface and strongly contrasting band are consistent with silica-rich jasper, though the host may be altered volcanic rock.
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Physical properties
Hardness about 6.5–7 Mohs; opaque red-orange and gray, with earthy to vitreous luster and no visible cleavage. The polished/tumbled surface and strongly contrasting band are consistent with silica-rich jasper, though the host may be altered volcanic rock.
Formation & geological history
Formed when silica-rich fluids replaced or cemented fine sediments or volcanic material, with hematite/goethite producing the red color; exact age and locality cannot be determined from the image. Such material commonly forms in hydrothermal veins, breccias, and ancient volcanic terrains.
Uses & applications
Used for cabochons, beads, carvings, tumbled stones, and ornamental objects; not generally a construction stone in small specimens. Collector value is mainly aesthetic and locality-dependent.
Geological facts
The red band is likely iron-oxide-rich jasper rather than a separate crystal vein. Jasper is a cryptocrystalline variety of quartz, so individual crystals are normally invisible.
Field identification & locations
Identify by its opaque, dense appearance, waxy/vitreous polish, high hardness, and inability to scratch with a steel knife easily; a streak test may show white to reddish powder. Common worldwide, especially in volcanic and iron-rich regions.
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