1 Physical Properties
1.1 Tenacity
1.2 Solubility
Decomposed by acids
Not Available
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Not Available
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
1.6 Cleavage
Perfect on {010}
None, may show partings on {0001} and {10 1 1}
1.7 Mohs Hardness
1.8 Chemical Composition
(K,Na)3Cu20Al3Si29O76(OH)16•~8(H2O)
Fe 2O 3Arthur Thomas , Gemstones (2009)