Basalt Pebble

Hardness: 6 on Mohs scale, Color: Dark grey to black or brownish-black, Luster: Dull to sub-metallic, Texture: Fine-grained (aphanitic), Specific Gravity: 2.8-3.0

Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the surface of a terrestrial planet or moon. This specific pebble shows signs of natural stream or beach erosion, creating a smooth, rounded surface.

Commonly used as construction aggregate, crushed stone, road base, asphalt concrete paving, and in decorative landscaping or river-rock features.

Basalt is the most common rock type in the Earth's crust, making up most of the oceanic crust as well as large volcanic provinces on land like the Columbia River Basalt Group.

Identified by its dark color, heavy weight relative to size, fine-grained microcrystalline texture, and lack of visible large quartz crystals. Very common along riverbeds, beaches, and volcanic regions.