mineral
Polished/tumbled brown stone, likely brown jasper or chert
Microcrystalline quartz (SiO₂), probably jasper/chert; exact identification requires testing
AI-generated identification · may be incorrectOpaque orange-brown, smooth tumbled surface, dull to slightly waxy luster, no visible cleavage, and likely Mohs hardness about 6.5–7. Specific gravity is approximately 2.6–2.7.
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Physical properties
Opaque orange-brown, smooth tumbled surface, dull to slightly waxy luster, no visible cleavage, and likely Mohs hardness about 6.5–7. Specific gravity is approximately 2.6–2.7.
Formation & geological history
Formed from silica-rich fluids or sediment producing microcrystalline quartz, commonly with iron-oxide coloration. The natural material may be Paleozoic or younger; tumbling is human processing and obscures original texture.
Uses & applications
Used as a lapidary stone, cabochon, ornament, paperweight, or inexpensive collectible; occasionally used for beads and small carvings.
Geological facts
Jasper and chert are varieties of cryptocrystalline quartz and can look nearly identical when polished. The reddish-brown color commonly comes from hematite or limonite inclusions.
Field identification & locations
Look for glassy fracture, absence of cleavage, and inability to scratch it with a steel knife; it should scratch window glass, though testing a polished specimen may damage it. Common sources include India, Madagascar, Brazil, the United States, and Mexico.
