Madagascar sapphire is corundum from the alluvial and primary deposits of southern, central and northern Madagascar. Since the discovery of the Ilakaka and Sakaraha gem fields in 1998, Madagascar has been the largest producer of sapphire by volume in the world, supplying as much as half of global production in some years and reshaping the trade architecture of the species.

The principal sources

Ilakaka and Sakaraha (south central Madagascar) yield alluvial blue, pink, padparadscha-like, yellow and fancy-colour sapphires, including a large output of so-called Ceylon-type pastel material. Andranondambo (south-east) is a primary skarn-hosted deposit producing fine blue sapphire with a colour signature similar to classic Sri Lankan goods. Ambondromifehy (north) is a basalt-related source of darker blue stones, often with the colour zoning typical of basalt-related Australian and Thai material. Diego (north) and Bemainty/Ambatondrazaka (eastern) round out the modern producing fields.

Treatment and trade

Heat treatment is overwhelmingly common; commercial Madagascan sapphire is largely heated, often with multiple cycles to refine colour. Beryllium diffusion has been documented in some yellow and orange material, particularly through Bangkok cutting houses, and disclosure is required under all major laboratory and trade-association protocols. Lattice diffusion of titanium into surface layers has also been reported. Unheated stones with fine colour, particularly from Andranondambo and Bemainty, command significant premiums.

Origin determination

Madagascan sapphires from different deposits show distinct trace-element profiles. Ilakaka stones often plot in the metamorphic field with characteristics overlapping Sri Lanka, while Ambondromifehy material shows the iron-rich basalt-related signature. Major laboratories combine inclusion suites with trace-element chemistry to make confident origin calls, although separation from Sri Lankan goods on individual stones can remain challenging for fine pastel material.