Apatite and Sillimanite Physical Properties

Apatite and Sillimanite Chemical Formula

While comparing Apatite and Sillimanite physical properties, the important data you should know is its chemical composition. Since chemical formula defines the molecular structure of the crystal, most of the physical properties like color, tenacity, solubility are governed by Apatite and Sillimanite chemical formula.

• Chemical formula of Apatite- Ca 5(PO 4) 3(F,OH,Cl)Walter Schumann , Gemstones of the world (2001) More from other references
• Chemical formula of Sillimanite- Al 2SiO 5Michael O’Donoghue , Gems, Sixth Edition (2006)

Apatite and Sillimanite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Apatite and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Apatite and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Apatite is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.