A truly rare, large and continuous aggregate of Grandidierite, one of Madagascar’s most exceptional and sought-after minerals, naturally embedded in a contrasting host-rock matrix.
The specimen presents the Grandidierite in its original geological setting, with interconnected crystal growth rather than isolated fragments—a particularly desirable feature for serious mineral collectors.
Grandidierite is a magnesium–iron–aluminium borosilicate that crystallises in the orthorhombic system.
Its characteristic colours range from blue-green and sea-green to deep bluish green, often accompanied by a striking trichroic pleochroism: the colour can change noticeably depending on the viewing direction.
The mineral was first discovered in southern Madagascar in 1902 and was named after the French explorer and naturalist Alfred Grandidier.
