metamorphic
Greenstone (Epidosite / Chlorite Schist)
Metabasalt (often contains Epidote Ca2Al2(Fe3+,Al)(SiO4)(Si2O7)O(OH) or Chlorite)
Hardness: 6-7 (Mohs); Color: dull grayish-green to pistachio green; Luster: dull to vitreous; Crystal structure: massive or foliated; Cleavage: poor; Specific gravity: 2.8-3.0.
- Hardness
- 6-7 (Mohs)
- Color
- dull grayish-green to pistachio green
- Luster
- dull to vitreous
Identified More metamorphic →
Explore Greenstone (Epidosite / Chlorite Schist) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs); Color: dull grayish-green to pistachio green; Luster: dull to vitreous; Crystal structure: massive or foliated; Cleavage: poor; Specific gravity: 2.8-3.0.
Formation & geological history
Formed through the low-grade regional metamorphism of mafic igneous rocks (such as basalt) under relatively low temperature and pressure conditions, often in subduction zones or orogenic belts.
Uses & applications
Used historically for stone tools and axes; currently used as crushed stone for road construction, decorative gravel, and occasionally for lapidary work if the color is vibrant.
Geological facts
The term 'greenstone' was famously used by archaeologists to describe hard, green stones used by Neolithic cultures to create 'celt' axes. Geologically, it signifies the 'greenstone facies' of metamorphism.
Field identification & locations
Identify in the field by its characteristic green hue (due to chlorite, actinolite, or epidote) and its toughness compared to sedimentary rocks. Found in ancient shield areas like the Appalachians or the Canadian Shield.
More like this
