igneous
Basalt (Crushed Stone)
Basalt
Hardness: 6; Color: Dark grey to black; Luster: Dull/Sub-metallic; Structure: Aphanitic (fine-grained); Specific Gravity: 2.8-3.0
- Hardness
- 6
- Color
- Dark grey to black
- Luster
- Dull/Sub-metallic
Identified More igneous →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6; Color: Dark grey to black; Luster: Dull/Sub-metallic; Structure: Aphanitic (fine-grained); Specific Gravity: 2.8-3.0
Formation & geological history
Formed through the rapid cooling of magnesium-rich and iron-rich lava at or near the surface of a terrestrial planet or moon. Most basalt on Earth is less than 200 million years old.
Uses & applications
Primarily used as an aggregate in construction, road base, concrete, and railroad ballast. Occasionally used for high-end countertops or stone flooring.
Geological facts
Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. It is also found on the Moon, Mars, and Venus.
Field identification & locations
Identify by its dark color, heavy weight for its size, and absence of large visible crystals. Commonly found in volcanic regions or as gravel in urban landscapes.
