igneous
Olivine Basalt
Mafic Volcanic Rock (rich in (Mg, Fe)2SiO4)
Hardness: 6-7 on Mohs scale. Color: Dark gray to black matrix with olive-green phenocrysts. Luster: Dull (matrix) to vitreous (crystals). Structure: Aphanitic with porphyritic texture. Specific gravity: 2.8-3.0.
- Hardness
- 6-7 on Mohs scale
- Color
- Dark gray to black matrix with olive-green phenocrysts
- Luster
- Dull (matrix) to vitreous (crystals)
Identified More igneous →
Explore Olivine Basalt in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on Mohs scale. Color: Dark gray to black matrix with olive-green phenocrysts. Luster: Dull (matrix) to vitreous (crystals). Structure: Aphanitic with porphyritic texture. Specific gravity: 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the Earth's surface. These specimens are typically associated with oceanic crust and volcanic hotspots.
Uses & applications
Used in construction as crushed stone or aggregate. High-quality olivine crystals (peridot) are used in jewelry. Also used as a flux in steel making.
Geological facts
Olivine is one of the first minerals to crystallize from a cooling magma. Some olivine-rich rocks (peridotites) originate from the Earth's mantle and are brought to the surface by volcanic eruptions.
Field identification & locations
Identify by looking for green, glassy 'grains' embedded in a dark, heavy rock. Found in volcanic regions like Hawaii, Iceland, and the Canary Islands. It is magnetic if high in iron content.
