metamorphic
Greenstone
Chlorite schist or Epidosite
Hardness: 6-7 (if dominated by epidote/quartz); Color: Dull to dark green; Luster: Matte to slightly waxy; Crystal structure: Fine-grained/Aphanitic; Specific gravity: 2.6 – 3.3.
- Hardness
- 6-7 (if dominated by epidote/quartz)
- Color
- Dull to dark green
- Luster
- Matte to slightly waxy
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Physical properties
Hardness: 6-7 (if dominated by epidote/quartz); Color: Dull to dark green; Luster: Matte to slightly waxy; Crystal structure: Fine-grained/Aphanitic; Specific gravity: 2.6 – 3.3.
Formation & geological history
Formed through low-grade metamorphism of mafic igneous rocks like basalt or gabbro, typically in seafloor hydrothermal environments or orogenic belts.
Uses & applications
Used historically for stone tools and weapons (axes); currently used as crushed stone for construction, architectural veneer, or polished as river stones for landscaping and small carvings.
Geological facts
The green color comes from minerals like chlorite, epidote, or actinolite. Greenstone belts represent some of the oldest preserved rocks on Earth, dating back to the Archean Eon.
Field identification & locations
Identify by its characteristic 'sea-foam' or 'avocado' green hue and lack of visible crystalline structure. Look for it in high-energy river beds or coastal areas near ancient volcanic zones.
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