igneous
Tumbled black stone, likely basalt or black jasper
Basalt (fine-grained plagioclase–pyroxene rock), possibly opaque microcrystalline quartz/jasper
AI-generated identification · may be incorrectDark gray-black, smoothly polished, opaque, with subdued vitreous to waxy luster and faint flow-like streaks; likely Mohs hardness 5.5–7, no visible crystals or cleavage. The rounded shape indicates tumbling or water wear.
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Physical properties
Dark gray-black, smoothly polished, opaque, with subdued vitreous to waxy luster and faint flow-like streaks; likely Mohs hardness 5.5–7, no visible crystals or cleavage. The rounded shape indicates tumbling or water wear.
Formation & geological history
If basalt, it formed from rapidly cooled mafic lava, commonly in volcanic flows ranging from ancient to geologically recent; if jasper, it formed by silica-rich replacement or sedimentary deposition. Exact identification requires hardness, streak, and density tests.
Uses & applications
Used as a decorative stone, worry stone, paperweight, or lapidary material; basalt is also important for aggregate and construction, while jasper is used in cabochons and carvings.
Geological facts
Its very smooth, heart-like form and reflective surface are consistent with a polished commercial stone rather than an exposed natural outcrop.
Field identification & locations
Look for tiny feldspar or pyroxene grains and a gray streak for basalt; jasper is usually harder and gives a white streak. Common sources include volcanic regions worldwide and commercial tumbling operations.
