Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
slightly water soluble and in hot hydrochloric acid
Subconchoidal, Uneven, ConchoidalWalter Schumann
Octahedral, perfect on {111}, parting on {011}
Perfect on {001}, imperfect on {110}
(K,Na)Ca4Si8O20(F,OH)•8(H2O)