mineral
Pale green tumbled mineral, likely prehnite
Prehnite — Ca₂Al(AlSi₃O₁₀)(OH)₂; identification is provisional from the photograph
AI-generated identification · may be incorrectPale yellow-green, translucent, vitreous to pearly luster, apparently polished/tumbled with no visible crystal faces. Mohs hardness 6–6.5; specific gravity about 2.8–2.95; typically orthorhombic and commonly botryoidal or massive, with imperfect cleavage.
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Physical properties
Pale yellow-green, translucent, vitreous to pearly luster, apparently polished/tumbled with no visible crystal faces. Mohs hardness 6–6.5; specific gravity about 2.8–2.95; typically orthorhombic and commonly botryoidal or massive, with imperfect cleavage.
Formation & geological history
Forms as a low-temperature hydrothermal mineral in cavities and fractures of basalt and other volcanic rocks, often alongside zeolites and quartz. It is commonly associated with relatively young volcanic terrains, though its exact age cannot be determined visually.
Uses & applications
Used mainly as a collectible or lapidary stone; attractive translucent material is cut into cabochons and beads. It has little industrial or construction value.
Geological facts
The specimen appears to sit on a metal surface, but its pale green translucent appearance is consistent with polished prehnite. Similar-looking alternatives include pale jade/nephrite, serpentine, chrysoprase, fluorite, or dyed glass.
Field identification & locations
Prehnite is common in basaltic volcanic provinces, including parts of northeastern Queensland, making it regionally plausible near Townsville. Confirm with hardness testing: it should scratch glass but not quartz; check specific gravity and avoid destructive testing if valuable.
