1 Physical Properties
1.1 Tenacity
Not Available
Not Available
1.2 Solubility
Not Available
Not Available
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalGemdat.org, Uneven
1.6 Cleavage
Good on {100}
{111} Indistinct, {111} Indistinct, {111} Indistinct
1.7 Mohs Hardness
1.8 Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Fe2+ Al 2O 4Gemdat.org , Management Team (2012)