What is "sillenite"

Sillénite or sillenite is a mineral with the chemical formula BiSiO. It is named after the Swedish chemist Lars Gunnar Sillén, who mostly studied bismuth-oxygen compounds. It is found in Australia, Europe, China, Japan, Mexico and Mozambique, typically in association with bismutite.

The cubic crystal structure of sillénite is shared by several synthetic materials including bismuth silicon oxide, bismuth titanate and bismuth germanate.