London blue topaz and Blue John Chemical Formula
While comparing London blue topaz and Blue John 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 London blue topaz and Blue John chemical formula.
>- Chemical formula of Blue John- CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)