igneous
Polished black stone sphere (likely black basalt or black tourmaline)
Most likely fine-grained basalt (plagioclase–pyroxene); mineral identification is uncertain from the image alone
AI-generated identification · may be incorrectUniform matte-to-satin black, rounded and polished, with no visible crystals or cleavage. Likely hardness about 5–6 Mohs and specific gravity roughly 2.8–3.2; the surface may also be coated or artificially dyed.
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Physical properties
Uniform matte-to-satin black, rounded and polished, with no visible crystals or cleavage. Likely hardness about 5–6 Mohs and specific gravity roughly 2.8–3.2; the surface may also be coated or artificially dyed.
Formation & geological history
If basalt, it formed from rapidly cooled mafic lava, commonly in the Cenozoic or older volcanic terrains. Spherical shaping and polishing are human-made, so natural age cannot be determined from the object.
Uses & applications
Decorative sphere, meditation object, paperweight, or collector piece; basalt is also used as aggregate, dimension stone, and mineral wool feedstock.
Geological facts
The image cannot reliably distinguish basalt from obsidian, black tourmaline, soapstone, hematite, or manufactured glass/ceramic. A glassy shine, conchoidal fracture, or bubbles would suggest glass rather than stone.
Field identification & locations
Check an inconspicuous area for natural grain, test hardness against steel or quartz, and measure density; a magnet test may help if iron-rich. Common basalt sources include India, China, Mexico, and the western United States.
