1 Physical Properties
1.4 Tenacity
Not Available
Not Available
1.6 Solubility
Not Available
Not Available
1.7 Durability
Not Available
Not Available
1.8 Specific Gravity
2.58-2.643.34-3.44
1
7.18
5.4 Fracture
Not Available
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
5.5 Cleavage
Not Available
{111} Indistinct, {111} Indistinct, {111} Indistinct
5.6 Mohs Hardness
10.4 Chemical Composition
SiO 2Walter Schumann , Gemstones of the world (2001)
(K,Cs)Al 4Be 4(B,Be) 12O 28Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references