Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{001} Indistinct, {???} Indistinct
(Mg,Fe)Al 2(PO 4) 2(OH) 2Arthur Thomas , Gemstones (2009) More from other references
Perfect on [001] imperfect on [100]
(K,Na) 3(Fe2+ ,Mn) 7Ti 2Si 8O 24(O,OH) 7Anthony et al , Handbook of mineralogy (2001)