metamorphic
Greenstone
Chlorite schist / Meta-basalt
Hardness: 3.5-5.5 (Mohs scale), Color: Dull waxy green to dark gray-green, Luster: Greasy or earthy, Crystal Structure: Monoclinic (microcrystalline), Cleavage: Poor to slaty, Specific Gravity: 2.8-3.0
- Hardness
- 3
Identified More metamorphic →
Explore Greenstone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5-5.5 (Mohs scale), Color: Dull waxy green to dark gray-green, Luster: Greasy or earthy, Crystal Structure: Monoclinic (microcrystalline), Cleavage: Poor to slaty, Specific Gravity: 2.8-3.0
Formation & geological history
Formed through the regional metamorphism of mafic igneous rocks (like basalt or gabbro) at low temperature and high pressure during mountain-building events. Typically Paleozoic to Precambrian in age.
Uses & applications
Used historically for stone tools and carvings; currently used for decorative stone, garden gravel, and occasionally as a minor gemstone when polished.
Geological facts
The green color is primarily due to the presence of secondary minerals like chlorite, epidote, and actinolite. It is often found in 'greenstone belts' which are some of the oldest parts of the Earth's crust.
Field identification & locations
Identify by its distinctive dull green hue and lack of visible coarse crystals. Often found in riverbeds or coastal areas near ancient volcanic zones. It is softer than quartz and can often be scratched by steel.
More like this
