Madagascar, the large island off the southeast coast of Africa, is one of the most varied gem sources on Earth. Its pegmatites have yielded tourmaline, morganite and other beryls for more than a century, and since the 1990s a series of sapphire discoveries, above all the Ilakaka rush that began in 1998, has made it one of the world's major sapphire producers. The island also supplies labradorite, apatite, garnet, ruby, emerald and many collector stones.
Why Madagascar has so many gems
Madagascar was once part of the supercontinent Gondwana, joined to Africa, India and Antarctica. Much of the island is made of very old metamorphic and igneous rocks that were folded and heated during mountain-building events hundreds of millions of years ago. The same broad belt of rocks continues into East Africa, southern India and Sri Lanka, which helps explain why these regions share many of the same gems.
Within these rocks, gem-bearing pegmatites formed from the last, mineral-rich fluids of cooling granite. Other gems grew in metamorphic rocks such as marble and schist. Erosion then freed many of these crystals and carried them into river gravels. The metamorphic rock and igneous rock pages explain these processes.
The Ilakaka sapphire rush
In 1998, sapphires were found near the village of Ilakaka in southwestern Madagascar, close to Isalo National Park. News spread quickly, and tens of thousands of people arrived to dig. A roadside hamlet grew within a few years into a sprawling mining town with dealers' offices, shops and makeshift housing.
The Ilakaka deposits are alluvial gravels spread over a wide area. They produce sapphire in an unusually broad range of colors: blue, pink, purple, yellow, orange, green and color-change, along with padparadscha-like pink-orange stones. Much of the rough is heated, often in Thailand or Sri Lanka, to improve color and clarity. Some material from Ilakaka resembles Sri Lankan sapphire closely, which made origin determination harder for gem labs. The rush also brought problems common to gem booms, including crime, unsafe pits and environmental damage.
Andranondambo sapphire
A few years before Ilakaka, in the 1990s, fine blue sapphire was found at Andranondambo in the far southeast of the island. These sapphires formed in skarn rocks, where hot fluids reacted with marble and other rocks. The best stones show a soft, velvety blue that drew comparisons with classic Kashmir sapphire. The deposit produced its finest material for a relatively short time, and Andranondambo stones are prized when they come up today.
Later sapphire finds in Madagascar, such as near Ambatondrazaka in the east, have produced fine blue stones as well. For how sapphires are treated, see sapphire treatments.
Tourmaline
Madagascar has been a classic source of tourmaline since the early 20th century. Pegmatites in the central highlands, especially around Antsirabe and the Betafo area, produce crystals in pink, red, green, blue and multicolor combinations. Slices cut across multicolor crystals show concentric color zones in triangular patterns.
The tourmaline species liddicoatite (now classed as fluor-liddicoatite) was first described from Malagasy material, and Madagascar became known for large crystals of it with dramatic color zoning. Some of the island's pegmatites, such as Anjanabonoina, have produced museum-quality specimens.
Morganite and other beryl
Morganite, the pink to peach variety of beryl, has a direct link to Madagascar. Pink beryl from the island was identified in the early 20th century and named in honor of the American banker and gem collector J.P. Morgan, at the suggestion of the gemologist George Frederick Kunz. Malagasy morganite is known for its clear pink color in sizable, clean crystals.
The island also produces aquamarine and emerald. Emerald deposits in the east, such as around Mananjary, are found in schists, similar to many other African emerald sources.
Labradorite
Madagascar is a major source of labradorite, a feldspar that shows flashes of blue, green, gold and orange called labradorescence when light hits it at certain angles. The effect comes from light interfering with thin layers inside the stone. Malagasy labradorite is mined mostly in the south and is widely used for cabochons, beads, carvings and polished slabs.
Apatite
Madagascar produces bright blue to blue-green apatite, often called "neon" apatite in the trade for its glowing color. Apatite is soft for a gem, about 5 on the Mohs scale, so it is better suited to earrings and pendants than to rings that take daily knocks. Most Malagasy apatite is sold untreated, though some may be heated to change its color.
Other Malagasy gems
The island's output goes well beyond these headline stones. Madagascar also produces:
- Ruby, from several deposits including some in the east of the island.
- Garnet, including demantoid andradite and spessartite.
- Chrysoberyl and alexandrite.
- Spinel, kunzite, zircon and quartz varieties.
- Collector stones such as grandidierite, a rare blue-green mineral first described from Madagascar.
Mining and trade
Most Malagasy gems come from small-scale and artisanal miners working by hand, often in remote areas. Rough is sold to local buyers and exporters, and much of it leaves the island uncut. Sapphire and ruby often travel to Thailand or Sri Lanka for heating and cutting before reaching jewelers.
Madagascar has periodically changed its rules on gem exports, and the trade has faced challenges with informal sales, smuggling and the rights of local miners. Buyers who care about origin and sourcing should ask sellers what they know about a stone's path from mine to market.
Frequently asked questions
What gems come from Madagascar?
Madagascar produces sapphire in many colors, tourmaline, morganite, aquamarine, emerald, ruby, labradorite, apatite, garnet, chrysoberyl and many rarer minerals. It is one of the most varied gem sources in the world.
What was the Ilakaka sapphire rush?
In 1998, sapphires were found near Ilakaka in southwestern Madagascar. Tens of thousands of miners arrived, and the area became one of the world's major sapphire sources, producing stones in a wide range of colors.
Is morganite from Madagascar?
Morganite was named from pink beryl found in Madagascar in the early 20th century, and the island remains a classic source. Morganite is also mined in Brazil and other countries.