metamorphic
Polished ruby-in-zoisite (anyolite), likely
Ruby-bearing zoisite: zoisite Ca₂Al₃(SiO₄)₃(OH), with corundum Al₂O₃ and commonly amphibole
AI-generated identification · may be incorrectTypically green, black, and red-brown, with a waxy to vitreous luster and mottled texture; hardness is about 6–7 (ruby locally 9), with no prominent cleavage and specific gravity around 3.3–3.4. The polished surface and irregular color patches match this material, though image-only identification is approximate.
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Physical properties
Typically green, black, and red-brown, with a waxy to vitreous luster and mottled texture; hardness is about 6–7 (ruby locally 9), with no prominent cleavage and specific gravity around 3.3–3.4. The polished surface and irregular color patches match this material, though image-only identification is approximate.
Formation & geological history
Forms during regional metamorphism of aluminum-rich rocks, where zoisite and ruby crystallize together; economically important deposits are chiefly associated with Neoproterozoic metamorphic rocks near Longido, Tanzania. Geological formation is generally hundreds of millions of years old.
Uses & applications
Commonly cut into cabochons, carvings, beads, and display stones; attractive specimens are valued more for color contrast than gem transparency.
Geological facts
The trade name “anyolite” refers to the green zoisite–ruby–black amphibole association, while “ruby zoisite” is the usual lapidary name.
Field identification & locations
Identify by vivid green zoisite, red ruby patches, black amphibole, and relatively high hardness; a streak, hardness, or mineralogical test is needed for confirmation. Commonly found in Tanzania, with related material elsewhere in East Africa.
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