igneous
Vesicular Basalt with Peridot (Olivine) Inclusions
Mafic extrusive igneous rock with (Mg, Fe)2SiO4 phenocrysts
Hardness: 6-7 (olivine) and 5-6 (basalt matrix); Color: Dark grey to black groundmass with yellowish-green crystals; Luster: Vitreous to dull; Crystal structure: Orthorhombic olivine in an aphanitic matrix; Specific gravity: approx 2.9-3.3
- Hardness
- 6-7 (olivine) and 5-6 (basalt matrix)
- Color
- Dark grey to black groundmass with yellowish-green crystals
- Luster
- Vitreous to dull
Identified More igneous →
Explore Vesicular Basalt with Peridot (Olivine) Inclusions in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (olivine) and 5-6 (basalt matrix); Color: Dark grey to black groundmass with yellowish-green crystals; Luster: Vitreous to dull; Crystal structure: Orthorhombic olivine in an aphanitic matrix; Specific gravity: approx 2.9-3.3
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at the Earth's surface. The olivine crystals (peridot) formed early in the cooling process at high temperatures within the magma chamber before being erupted.
Uses & applications
Used primarily as a specimen for collectors, decorative landscaping, and occasionally the olivine crystals are extracted for use as peridot gemstones if they are of sufficient size and clarity.
Geological facts
This specific texture is often referred to as porphyritic. Olivine is one of the first minerals to crystallize from a cooling magma and is a primary component of the Earth's upper mantle.
Field identification & locations
Identified by the distinct contrast between the dark, fine-grained or vesicular basaltic matrix and the glassy green olivine crystals. Commonly found in volcanic regions like Hawaii, Arizona, and Iceland.
