metamorphic
Greenstone / Quartzite Pebble
Metamorphosed Quartz-rich Rock
Hardness: 6-7 on Mohs scale; Color: Sage green, grey, and tan with dark veining; Luster: Vitreous to waxy when wet/polished; Crystal structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 6-7 on Mohs scale
- Color
- Sage green, grey, and tan with dark veining
- Luster
- Vitreous to waxy when wet/polished
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Sage green, grey, and tan with dark veining; Luster: Vitreous to waxy when wet/polished; Crystal structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone or basaltic precursors. This specimen has been significantly water-worn into a smooth, oval shape, likely in a river or coastal environment.
Uses & applications
Commonly used for lapidary work (tumbling), decorative landscaping, and as garden pebbles. High-quality greenstone can be used for jewelry or small carvings.
Geological facts
Greenstones often derive their color from minerals like chlorite, epidote, or actinolite. These rocks are frequently found as 'river rocks' and represent ancient crustal fragments that have undergone intense heat and pressure.
Field identification & locations
Identify in the field by its hardness (will scratch glass), smooth water-worn texture, and distinct greenish-grey bands. Common in glacial till and high-energy riverbeds.
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