igneous
Basalt (Tumbled Massage Stone)
Extrusive Igneous Rock
Hardness: 6 on the Mohs scale; Color: Dark grey to black; Luster: Dull to sub-vitreous; Crystal structure: Aphanitic (fine-grained), often vesicular; Specific Gravity: 2.8 - 3.0
- Hardness
- 6 on the Mohs scale
- Color
- Dark grey to black
- Luster
- Dull to sub-vitreous
Identified More igneous →
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Physical properties
Hardness: 6 on the Mohs scale; Color: Dark grey to black; Luster: Dull to sub-vitreous; Crystal structure: Aphanitic (fine-grained), often vesicular; Specific Gravity: 2.8 - 3.0
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the Earth's surface.
Uses & applications
Commonly used in landscaping, construction aggregate, and specifically shaped and polished for hot stone massage therapy.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forming much of the volcanic islands such as Hawaii.
Field identification & locations
Identified by its dark, fine-grained, heavy appearance. Tumbled and polished specimens used for massage are smooth, retain heat well, and can be found globally in volcanic regions.
