igneous
Dark, fine-grained rock fragment; possibly basalt
Undetermined; basalt is a tentative identification from the image
AI-generated identification · may be incorrectGray-brown, rough and granular, with a small tan patch; crystal size and luster are unclear. Hardness, cleavage, and specific gravity cannot be reliably determined from the photo.
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Physical properties
Gray-brown, rough and granular, with a small tan patch; crystal size and luster are unclear. Hardness, cleavage, and specific gravity cannot be reliably determined from the photo.
Formation & geological history
If basalt, it formed when iron- and magnesium-rich lava cooled at or near the surface; basalt occurs from ancient to modern volcanic settings. The image does not establish the specimen’s age or confirm its rock type.
Uses & applications
Common basalt is used as crushed aggregate, road stone, and building material; this small fragment has no evident commercial or jewelry use.
Geological facts
A fresh broken surface and tests for hardness, density, and reaction to dilute acid can help distinguish basalt from other dark rocks.
Field identification & locations
The specimen is palm-sized and apparently unpolished, but the image alone is insufficient for confident identification; inspect its texture and mineral grains in person.
