Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{010} Perfect, {001} Distinct
Fe3+ PO 4 · 2H 2OAnthony et al , Handbook of Mineralogy (2001)
Al 2SiO 5Arthur Thomas , Gemstones (2009) More from other references