What is "kyawthuite"

Kyawthuite is a rare mineral with a simple formula: BiSbO4. It is a natural bismuth antimonate. Kyawthuite is monoclinic, with space group I2/c, and is isostructural with clinocervantite, its trivalent- antimony-analogue. Kyawthuite is also an antimony-analogue of clinobisvanite. Kyawthuite was discovered in the vicinity of Mogok township in Myanmar, an area famous of various gemstone minerals.