igneous
Likely rounded dark pebble
Indeterminate; possibly basalt, diabase, or a dark chert/river pebble
AI-generated identification · may be incorrectSmall, smoothly water-worn, dark gray-green, and apparently fine-grained with a dull to faintly waxy luster. Hardness cannot be determined visually; basalt is typically Mohs 5–6, while chert is about 7; no visible cleavage or crystals.
Identified More igneous →
Explore Likely rounded dark pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Small, smoothly water-worn, dark gray-green, and apparently fine-grained with a dull to faintly waxy luster. Hardness cannot be determined visually; basalt is typically Mohs 5–6, while chert is about 7; no visible cleavage or crystals.
Formation & geological history
Likely formed as a volcanic or silica-rich rock and rounded by stream, beach, or glacial transport; its geological age cannot be established from the image. The uniform surface may also reflect weathering or polishing.
Uses & applications
Common pebbles have little commercial value, though attractive pieces may be used for crafts, landscaping, or casual collections; this specimen is not gem-quality based on appearance.
Geological facts
The blurred image prevents confident mineral identification. A streak, hardness, density, and fresh-surface examination would distinguish basalt from chert or other dark rocks.
Field identification & locations
Test whether it scratches glass (chert usually does; basalt generally does not), inspect a fresh chip for crystals, and use a magnet and streak plate cautiously. Dark rounded pebbles are common in river gravels, beaches, and glacial deposits worldwide.
