Madagascar mandarin garnet is the saturated orange variety of spessartite (manganese-aluminium garnet) recovered chiefly from the Bekily belt in southern Madagascar and from secondary alluvial workings further north. The deposit emerged commercially in the late 1990s, following the Namibian Kunene mandarin garnet discovery of 1991 that had popularised the trade name, and Madagascar has since become the principal commercial source for the variety.

Material character

The most desirable stones show a pure vivid orange of medium to medium-dark tone, free of the brownish modifier that downgrades typical orange spessartite. The classic Madagascan goods are slightly more yellowish than the original Namibian Kunene material, but well-cut stones above three carats can rival fine Kunene production in saturation. Refractive index sits at the high end of the garnet range, often above 1.79, and specific gravity around 4.15 helps distinguish spessartite from other orange gems by simple density testing.

Inclusion scenes are characteristic and useful for identification: feathers, irregular wavy growth tubes, fluid inclusions and occasional ilmenite or rutile platelets. Stones are typically eye-clean to slightly included; large clean rough exists but is uncommon, and stones above ten carats are scarce.

Trade and treatment

Mandarin garnet is unenhanced; no heat or filling treatment is in commercial use. Most rough is exported through Antananarivo to Bangkok, Chanthaburi and increasingly to Indian cutting centres. The species is durable, with hardness around 7 to 7.5, and is well-suited for ring use.

Trade nomenclature varies: some laboratories label the goods spessartine, the strict mineralogical species name, while others retain the historic spessartite. Mandarin garnet remains a marketing term and not a gemmological one, although it is well-established for the saturated orange material specifically.