1 Physical Properties
1.1 Tenacity
1.2 Solubility
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Gems, Sixth Edition (2006)
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), (e.g. graphite).
1.6 Cleavage
None
Distinct on {001} and {110}, indistinct on {100}
1.7 Mohs Hardness
1.8 Chemical Composition
SiO2 (with a high level of nickel impurities )
Pb 2(CO 3)Cl 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references