igneous
Epidote and Quartz in Basalt Porpohyry
Epidote bearing Porphyritic Basalt with Quartz Veins
Hardness 6-7 (epidote/quartz), Color: dark grey-purple groundmass with lime-green epidote and white quartz veins, Luster: Vitreous to dull, Crystal structure: monoclinic (epidote) and trigonal (quartz)
Identified More igneous →
Explore Epidote and Quartz in Basalt Porpohyry in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 6-7 (epidote/quartz), Color: dark grey-purple groundmass with lime-green epidote and white quartz veins, Luster: Vitreous to dull, Crystal structure: monoclinic (epidote) and trigonal (quartz)
Formation & geological history
Formed through volcanic cooling (igneous groundmass) followed by hydrothermal alteration (metasomatism) where hot fluids deposited minerals like epidote and quartz into rock fractures.
Uses & applications
Primarily of interest to collectors and geologists; epidote can be used as a semi-precious gemstone when found in high-grade crystals.
Geological facts
The distinctive pistachio-green color is a primary diagnostic feature of epidote. The presence of these minerals together indicates that the host rock underwent low-grade metamorphism.
Field identification & locations
Identify by looking for the 'pistachio' green streaks against a dark volcanic matrix. Commonly found in subduction zones or volcanic terranes. Collectors look for sharp color contrast between the green, white, and dark host rock.
