|
| Name Origin | - |
|---|---|
| Chemical Formula | (Mg, Fe)Al3BSiO9 |
| Color | Blue-green; translucent |
| Hardness | 7.5 on Mohs Scale |
| Crystal System | Orthorhombic. Crystals elongated and not well formed; massive. |
| Cleavage | Perfect 1 direction, good 1 direction |
| Specific Gravity (SG) | 2.97 - 3.0 |
| Pleochroism | Strong: dark blue-green/colorless/dark green |
| Luster | Vitreous |
| Occurrence |
Generally in pegmatites |
| Stone sizes |
Cut as cabochons up to about 1 inch (1-10 carats) |
Note: Grandidierite is a rather rare mineral, with a lovely blue-green color. It is never transparent, but cabochons from translucent material are quite attractive. The high hardness makes it suitable for wear, although the cleavage is good. Cut Grandidierite is only seen in collections, because few collectors know it exists it cuttable form.
Grandidierite gemstone
Photo Credit:
"Grandidierit-G-EmpireTheWorldOfGems" by DonGuennie (G-Empire The World Of Gems) - Own work http://www.g-empire.de. Licensed under CC BY-SA 3.0 via Commons - https://commons.wikimedia.org/wiki/File:Grandidierit-G-EmpireTheWorldOfGems.jpg#/media/File:Grandidierit-G-EmpireTheWorldOfGems.jpg
"Grandidierit-G-EmpireTheWorldOfGems" by DonGuennie (G-Empire The World Of Gems) - Own work http://www.g-empire.de. Licensed under CC BY-SA 3.0 via Commons - https://commons.wikimedia.org/wiki/File:Grandidierit-G-EmpireTheWorldOfGems.jpg#/media/File:Grandidierit-G-EmpireTheWorldOfGems.jpg