metamorphic
Green Quartzite
Silicon Dioxide (SiO2) with inclusions (e.g., Fuchsite or Actinolite)
Hardness: 7 on Mohs scale; Color: pale green to mottled sage green with white quartz veins; Luster: vitreous to waxy when water-worn; Crystal Structure: Trigonal (microcrystalline aggregate); Cleavage: none, uneven or conchoidal fracture; Specific Gravity: ~2.65.
- Hardness
- 7 on Mohs scale
- Color
- pale green to mottled sage green with white quartz veins
- Luster
- vitreous to waxy when water-worn
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Physical properties
Hardness: 7 on Mohs scale; Color: pale green to mottled sage green with white quartz veins; Luster: vitreous to waxy when water-worn; Crystal Structure: Trigonal (microcrystalline aggregate); Cleavage: none, uneven or conchoidal fracture; Specific Gravity: ~2.65.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone subjected to high heat and pressure. The greenish tint is typically derived from interstitial minerals like fuchsite (chromium-rich mica), chlorite, or actinolite.
Uses & applications
Used primarily in lapidary work, decorative beach stone collections, cabochons, carved ornaments, and landscape construction.
Geological facts
Beach pebbles of quartzite are shaped and smoothed over years of wave action, often displaying a greasy or polished look when wet. Green quartzite containing fine fuchsite is often called aventurine quartz if it displays a shimmering effect.
Field identification & locations
Identify in the field by its high hardness (scratches glass and steel), granular texture, lack of cleavage, and resistance to erosion compared to softer green minerals like serpentinite or talc. Commonly found along gravel beaches, riverbeds, and glaciated regions.
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