igneous
Basalt (with Brass Inlay)
Basalt (Mafic volcanic rock)
Hardness: 6-7 on Mohs scale; Color: Black to dark gray; Luster: Dull/Matte (polished in this specimen); Crystal Structure: Aphanitic (fine-grained); Specific Gravity: 2.8-3.0.
- Hardness
- 6-7 on Mohs scale
- Color
- Black to dark gray
- Luster
- Dull/Matte (polished in this specimen)
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Black to dark gray; Luster: Dull/Matte (polished in this specimen); Crystal Structure: Aphanitic (fine-grained); Specific Gravity: 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or very near the Earth's surface. Most basalt found on Earth's surface is less than 200 million years old due to tectonic recycling.
Uses & applications
Used widely in construction as aggregate, for floor tiles, and in artisanal crafts such as this carved decorative urn. It is also used as 'hot stones' in massage therapy due to its heat retention properties.
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 and Mars.
Field identification & locations
Identification in the field is based on its dark color, heavy weight (relative to size), and lack of visible crystals to the naked eye. In this context, it is identified as a hand-carved decorative vessel with metallic (brass) engraving.
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