Sillimanite and Lapis lazuli Physical Properties

Sillimanite and Lapis lazuli Chemical Formula

While comparing Sillimanite and Lapis lazuli 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 Sillimanite and Lapis lazuli chemical formula.

• Chemical formula of Sillimanite- Al 2SiO 5Michael O’Donoghue , Gems, Sixth Edition (2006)
• Chemical formula of Lapis lazuli- The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)₈Al₆Si₆O₂₄(S,SO)₄

Sillimanite and Lapis lazuli Specific Gravity

Another important criteria for qualitative analysis of gemstones is Sillimanite and Lapis lazuli Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sillimanite and Lapis lazuli Optical Properties during the identification of gemstone. Specific gravity of Sillimanite is 2.50-3.00 whereas that of Lapis lazuli is 2.50-3.00.