metamorphic

Ruby zoisite (anyolite)

Zoisite with corundum (ruby) and commonly amphibole; Ca₂Al₃(SiO₄)₃(OH)

AI-generated identification · may be incorrect

Hardness is about 6–7 for zoisite and 9 for ruby; typically green, pink to purplish-red, with black hornblende inclusions. It has a vitreous to waxy luster, granular crystalline structure, and poor cleavage; the specimen appears polished or naturally rounded.

Identified September 11, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when aluminum-rich rocks undergo regional metamorphism, producing green zoisite intergrown with ruby and amphibole. Most gem-quality material comes from Precambrian metamorphic terrains near Longido, Tanzania.

Uses & applications

Used as ornamental stone, cabochons, carvings, beads, and mineral specimens; contrasting green-and-ruby colors make it popular in jewelry. It is generally less valuable than transparent ruby.

Geological facts

The trade name “anyolite” specifically refers to the green zoisite–ruby–hornblende mixture. Color contrast and black amphibole patches are diagnostic of this attractive composite rock.

Field identification & locations

Identify it by mottled green zoisite, pink/red ruby zones, and occasional black amphibole; ruby may show a much higher hardness and glassier luster. Check locality information and avoid confusing it with dyed epidote or ruby-in-fuchsite.