mineral
Tumbled brecciated jasper
Jasper, a microcrystalline quartz variety (SiO₂), with iron-oxide-rich matrix or veining
AI-generated identification · may be incorrectOpaque reddish-brown and cream stone with a waxy to dull luster; quartz hardness is about 6.5–7 Mohs, no visible cleavage, cryptocrystalline structure, and specific gravity near 2.6. Its rounded shape indicates tumbling and polishing.
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Physical properties
Opaque reddish-brown and cream stone with a waxy to dull luster; quartz hardness is about 6.5–7 Mohs, no visible cleavage, cryptocrystalline structure, and specific gravity near 2.6. Its rounded shape indicates tumbling and polishing.
Formation & geological history
Forms when silica-rich groundwater cements or replaces sediment and rock fragments, commonly producing brecciation and iron-oxide coloration. The exact geological age and locality cannot be determined from the image.
Uses & applications
Used for cabochons, beads, carvings, ornamental objects, and inexpensive lapidary specimens; rarely used as aggregate or decorative stone.
Geological facts
Jasper is technically an opaque variety of chalcedony or microcrystalline quartz. Red coloration commonly comes from hematite or other iron oxides, while pale lines may represent quartz-rich cement or fracture fillings.
Field identification & locations
Identify it by its opaque appearance, red-brown iron staining, cream angular patterns, glassy edges when freshly broken, and inability to scratch it with a steel knife easily. Common sources include Oregon, Idaho, Utah, Madagascar, Brazil, and Australia.
