Sapphires from Madagascar
For the last ten years, Madagascar has experienced a sapphire rush. Although sapphires were known to exist in Madagascar as early as the 16th century, serious sapphire mining on the island is a relatively recent phenomenon due to the quality of the new finds. Sapphires from Madagascar resemble the stones from Sri Lanka, and some gemologists theorize that the two islands were once part of a single geological structure that was torn apart by plate tectonics.
Although sapphire deposits are known to exist all over the country, mining was banned in the northern portion of the island in the 1990s in an effort to protect indigenous species. In the south however, new discoveries of quality sapphires caused a massive migration to the area. Despite government attempts to regulate the industry, smuggling, corruption and environmental degradation were rife.
Many of the gem deposits in Madagascar have not yet been inventoried. This is particularly true of Ilakaka, which is rumored to be the world’s largest sapphire deposit of real economic value.
Madagascar has an extremely interesting geological history that has determined where sapphires are located. Sapphire deposits in the north come from alluvial deposits of weathered basaltic rocks, while those in the south have metamorphic origins. Mechanized mining is difficult given the scattered nature of the deposits and the high costs involved. Miners manually excavate pits 15 feet wide and up to 80 feet deep. Gravel is hauled from the pits and washed in nearby rivers.
The sapphires of Madagascar are usually blue, but colorless, pink, purple, orange, yellow, and green stones are also found. Padparadscha and color-change sapphires are also mined on the island. Characteristics include distinct color zoning, silk, fingerprint inclusions, and the fact that many of the stones respond well to heat treatment.