- Feldspar var. Sanidine
- Thumbnail, 2.8 x 2.4 x 1.0 cm
- Itrongay, Betroka District, Anosy Region, Tulear Province, Madagascar
The Itrongay region of Madagascar has produced the finest gem crystals of Sanidine. This exceptional thumbnail is very rare for the fine condition it is in. The crystal is 100% gem, golden, totally transparent, and euhedral. The faces are glassy and textured with small, curvy trenches that look like sub-parallel and tiny worm tracks. This gem Sanidine has a mass of about 12 grams. Specimens of this quality for both gemminess and luster with a good form at the same time are quite uncommon although they have trickled out slowly for years.