Sillimanite

$2,750.00

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T

The ArkenstoneFeatured

3,403 for sale·Member since 2026

Sillimanite is a relatively common metamorphic rock forming mineral, however, it very rarely forms in gem crystals like this amazing thumbnail! This elongated and slender prismatic, medium lavender colored crystal is gem throughout its length and has a touch of a satin luster largely from being slightly water worn. The prism faces are well-defined, however, it is unterminated and the edges of the crystal are slightly rounded by stream transport. This Sillimanite thumbnail gem displays noticeable pleochroism on a white phone or computer screen that varies from blue to purple-ish blue in perpendicular orientations. This little beauty has a mass of 6.49 grams. Such large, relatively sharp crystals as this are extremely rare in nature and this is significant.