The Archean crystalline area in Madagascar is rich in granite pegmatites and is a traditional supplier of gem beryl
, and, to a lesser degree, topaz
to world markets. The delicate peach-pink colour of morganite
is especially highly prized and is considered as the best in the world.
The Madagascar pegmatites are subdivided into the rare-metal pegmatites, muscovite-beryl pegmatites with niobo-tantalites; sodium-lithium pegmatites with spodumene, amblygonite, and lepidolite; and rare-earth pegmatites (including rare earth-uranium and monazite), which are distributed in more or less isolated pegmatite fields (Beus and Gerasimovsky, 1983)
and other gemstones are mined mainly from miarolitic pegmatites on the High Plateau north and southwest of the town of Antananarivo in the central part of the island.
Very high quality aquamarines
are found among the Madagascar stones. They are transparent with a wide range of colours from bluish green to azurite and deep dark blue to almost black. Pleochroism can be very strong and, as in cordierite
, changes from dark blue to pale blue and almost colourless. Density is 2.73 - 2.77 g/cm³. Thin channels parallel to the long axis of the crystal, which create a "rain effect", are rather typical.
Ref: E.Ya. Kievlenko, Geology of gems, 2003, p. 110 - 112
Gem list contains entries from all listed localities in region.
Gemstones from Madagascar by Colour
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Localities in this Region