Vesicular Basalt Pebble

Hardness 6 on Mohs scale, dark gray to black color, dull to earthy luster, fine-grained (aphanitic) texture with small pitted vesicles, no cleavage, high specific gravity (around 2.8 to 3.0)

Formed from the rapid cooling of low-viscosity basaltic lava erupted from volcanoes or mid-ocean ridges. Vesicles form when dissolved gases bubble out of the liquid lava as it cools. Smooth rounded shape produced by stream or beach erosion over time.

Basalt is crushed and used as construction aggregate, asphalt, and railroad ballast. Smooth stream pebbles are popular for landscaping, aquariums, garden decor, and rock painting.

Basalt is the most common rock type in the Earth's crust, making up most of the oceanic floor. It is also widespread on the Moon and Mars, forming the dark lunar plains known as 'maria'.

Identified by its fine-grained, dark mafic texture, small gas pockets (vesicles), and rounded stream-worn shape. Commonly found along riverbeds, beaches, and gravel paths near volcanic regions worldwide.