One of the rarest gems on Earth. Blue-green trichroism that shifts with every movement.
Grandidierite is trichroic — showing blue, green, and white at different crystal orientations. Faceted, transparent specimens of significant size are extraordinarily rare. For most of the 20th century it was known only in opaque form; the discovery of facetable material in Sri Lanka and Madagascar changed that.
Grandidierite was first described in 1902 by the French mineralogist Alfred Lacroix, from a specimen found in southern Madagascar. He named it in honour of Alfred Grandidier, the French explorer and naturalist who had spent decades documenting Madagascar's natural history. For the first century of its known existence, grandidierite was considered exclusively a mineral collector's specimen — transparent, gem-quality material was unknown. The discovery of facetable crystals in Sri Lanka in the 1990s and Madagascar in the 2010s opened a new chapter, but production remains sporadic and tiny.
Grandidierite is a stone for a specific collector — someone who values rarity over recognition, who understands that the most interesting stones are often the least famous. In design terms, trichroism creates an object that reads differently in every light condition: blue in one orientation, green in another, a ghostly white in a third. The setting must be open enough to allow all three aspects to be seen.
Faceted, transparent grandidierite above one carat is the target. The finest specimens show vivid blue-green with strong trichroism and minimal inclusions. Sri Lankan material is typically cleaner; Malagasy material sometimes shows stronger colour saturation. Because of its rarity, provenance documentation and laboratory certification are highly recommended. Buy the best you can afford — quality spread is extreme in this species.
Grandidierite keeps company with the rarest gems in existence
I source stones individually and can discuss what's currently available. Every piece is designed around the specific gem.
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