Tourmaline (hardness: 7-7.5 Mohs)
Complex aluminum borosilicate (Elbaite, Dravite, Uvite)
Specific gravity: 3.03-3.25
_Achorite_: Colorless
_Brazilian emerald_: Green
_Dravite_: Brown
_Indicolite_: Dark blue
_Rubellite_: Pink to red
_Siberite_: Violet
_Verdilite_: Green
Turquoise (hardness: 5-6 Mohs)
Hydrous copper aluminum phosphate
Specific gravity: 2.6-2.8