1 Physical Properties
1.1 Tenacity
1.2 Solubility
1.3 Durability
1.4 Specific Gravity
1.5 Fracture
Uneven, UnevenArthur Thomas, Gemstones (2009)
Uneven, Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001)
1.6 Cleavage
Distinct on {0001} imperfect on {11 2 0}
Perfect {010}, imperfect {100}
1.7 Mohs Hardness
1.8 Chemical Composition
Na 4(Ca,Ce) 2(Fe,Mn,Y)ZrSi 8O 22(OH,Cl) 2Ulrich Henn and Claudio C.
Ca2Al3(SiO4)3(OH)