1 Physical Properties
1.1 Tenacity
Not Available
Very brittle
1.2 Solubility
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
2.85-3.003.30-3.40
1
7.18
1.5 Fracture
Brittle, UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Conchoidal, Brittle, Conchoidal
1.6 Cleavage
Perfect
{010} perfect, {110} distinct, {100} in traces
1.7 Mohs Hardness
1.8 Chemical Composition
(Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references