Ruby in Zoisite

Ruby in zoisite, also called anyolite, is a natural metamorphic rock rather than a single mineral: bright green chromium-bearing zoisite containing opaque purplish-red to pink ruby (corundum) crystals, often with black to very dark green amphibole (pargasite, also described as hornblende or tschermakite). It was first reported in 1954 near Longido, Tanzania, and is cut into cabochons, beads, carvings and small sculptures.

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Full material guide
Material facts

What the material is, where it comes from or how it is made, identification and care, from the cited sources.

Properties

Nature Natural metamorphic rock (not a single mineral)
Components Green chromium-bearing zoisite; ruby (corundum, Al₂O₃); black to very dark green pargasite/hornblende
Color Green with purplish-red to pink spots and black specks
Transparency Opaque (the ruby crystals are also opaque)
Mohs hardness Zoisite groundmass 6.5

Origins & sources

Mindat describes anyolite as a granular mass of chrome-zoisite with pargasite and coarse ruby porphyroblasts up to several centimetres across, first reported in 1954 from the Longido District, Arusha Region, Tanzania, including the Mundarara Mine. The International Gem Society also names Longido, Tanzania, as the source of this material.

Identification

Ruby in zoisite is recognised by its green zoisite groundmass with red to pink ruby and black amphibole grains. Geology.com notes that ruby in fuchsite, a similar-looking material, is often misidentified as ruby in zoisite; fuchsite has a hardness of only 2 to 3, while zoisite is at least 6, and ruby in fuchsite usually shows blue kyanite rims around the ruby crystals, which do not occur in ruby in zoisite.

Care

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History & culture

History

The name anyolite comes from the Maasai word for green (given by Mindat as "anyole" and by the International Gem Society as "anyoli"). Mindat explains that it was chosen as a more euphonious name than a petrographic description such as "corundum-pargasite zoisitite" for the rock first reported in 1954 in Tanzania.

Cultural meanings

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Traditional beliefs

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Sources

Collected Oct 23, 2026