metamorphic
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
Hardness: 6-7 on Mohs scale; Color: Dull grayish-green to dark green; Luster: Matte to slightly waxy when polished; Crystal Structure: Fine-grained/aphanitic; Cleavage: None/conchoidal fracture; Specific gravity: 2.8-3.3.
- Hardness
- 6-7 on Mohs scale
- Color
- Dull grayish-green to dark green
- Luster
- Matte to slightly waxy when polished
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Dull grayish-green to dark green; Luster: Matte to slightly waxy when polished; Crystal Structure: Fine-grained/aphanitic; Cleavage: None/conchoidal fracture; Specific gravity: 2.8-3.3.
Formation & geological history
Formed through low-grade metamorphism (greenschist facies) of igneous rocks under high pressure and temperature. This specific specimen has been anthropogenically shaped by grinding and polishing during the Neolithic or later periods.
Uses & applications
Historically used as a functional tool (axe, adze, or chisel) and as a symbol of status or ritual object. Today, it is a significant archaeological and collector's item.
Geological facts
Commonly known as 'thunderstones' in folklore, these were believed to fall from the sky during storms. Greenstone was preferred by ancient peoples because it is extremely tough and resists shattering.
Field identification & locations
Identify by its symmetrical, tapered shape and bit-edge. Found in archaeological sites, riverbeds, and plowed fields worldwide. Collectors should look for signs of 'pecking' or grinding marks on the surface.
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