Purple of Cassius

Purple gold (also Cassius Cassius purple or gold ) is a pre 1676 by Andreas Cassius developed in Leiden color pigment. It is prepared by reduction of gold (III ) chloride in aqueous solution with tin ( II) chloride. The resulting purple colored solution contains colloidally bound gold tin dioxide as support material. It is very heat resistant and does not appear black in larger layer thickness.

Gold Purple is for the production of ruby glass ( gold ruby ​​glass), used in porcelain painting, glazes and enamel. Today ruby glass is largely replaced by a cheaper selenium- containing product.