Solid inclusions

Baddeleyite (Source B) (ZrO2)

Backscattered SEM image of baddeleyite inclusion (white) embedded in silicates (grey) in a matrix of a heat-treated rough sapphire (black) from Source A

Baddeleyite inclusions were found together with Mg-Al-spinel and Ca-Na-alumosilicates (most probably scapolite and anorthite) in a rough sapphire. This sapphire was one of the heat-treated samples. In these samples some of the silicates are transformed by heat treatment. However, baddeleyite and Mg-Al-spinel are unchanged. This is due to the fact that they have very high melting points - above those of corundum.

Very recently, baddeleyite was discovered as an inclusion in a sapphire from a basaltic source. It was formed by alteration reactions from zircon minerals and is not considered a primary mineral inclusion (Guo et al., 1996).