Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.33-2.375.5
1
7.18
👆🏻
Fracture
Uneven
Conchoidal
Cleavage
Perfect on {001}, imperfect on {110}
{111} Indistinct, {111} Indistinct, {111} Indistinct
Mohs Hardness
4.5-55-5.5
2
10
👆🏻
Chemical Composition
(K,Na)Ca4Si8O20(F,OH)•8(H2O)
(Ca,Na) 2Ta 2O 6(O,OH,F)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references