Good size crystal of pleonast, a variety of spinel containing Fe²⁺. It shows complex crystalline forms of the octahedron and combinations of the octahedron with the dodecahedron or, more rarely, with those of the cube. A museum size piece, very rare to get.

Rich group of grandidierite crystals, on matrix. Unusually well defined and aerial for the species. Brilliant, translucent and with an intense uniform bluish-green color. We can observe prismatic crystals with terminal faces. A sample of great quality for this rare nesosilicate. With the label of the collector.
Grandidierite was discovered by the French mineralogist, Alfred Lacroix in 1902 and named after French explorer and naturalist Alfred Grandidier (1836-1912), who wrote the great natural history book: "L'Histoire physique, naturelle et politique de Madagascar". The first reported locality for the species is at the cliffs of Andrahomana, on the southern coast of Madagascar. The species is a magnesium, iron, aluminum borosilicate and although it has been found in multiple localities around the world, it's still considered exceptionally rare, especially in gem quality material (mindat).

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From a classic locality for the species is coming this thorianite cube, with pointed faces of the octahedron, intense black color and brightness. The thorianite is a thorium oxide, almost always with some uranium content, the uranothorianite variety. This specimen contains about 5-6% by weight of uranium. We will send the analysis to the buyer.

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