Sillimanite and Iolite Physical Properties

Sillimanite and Iolite Chemical Formula

While comparing Sillimanite and Iolite 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 Iolite chemical formula.

• Chemical formula of Sillimanite- Al 2SiO 5Michael O’Donoghue , Gems, Sixth Edition (2006)
• Chemical formula of Iolite- Mg₂Al₄Si₅O₁₈

Sillimanite and Iolite Specific Gravity

Another important criteria for qualitative analysis of gemstones is Sillimanite and Iolite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sillimanite and Iolite Optical Properties during the identification of gemstone. Specific gravity of Sillimanite is 2.6-2.7 whereas that of Iolite is 2.6-2.7.