Clinocervantite
Clinocervantite is a monoclinic-prismatic mineral with a chemical formula of Sb3+Sb5+O4.[https://www.mindat.org/min-6879.html "Clinocervantite: Mineral information, data and localities"] mindat.org It was discovered in 1999 in cavities of waste rock at the Cetine Mine in Siena, Italy.[https://webmineral.com/data/Clinocervantite.shtml "Clinocervantite Mineral Data"] webmineral.com
Description
Clinocervantite is colorless or white and has a vitreous luster. It has a white streak.[https://rruff.geo.arizona.edu/AMS/minerals/Clinocervantite "Clinocervantite.pdf"] Handbook of Mineralogy
It is isostructural with kyawthuite. The name clinocervantite reflects its relationship with cervnatite. It is monoclinic-prismatic polymorph.[https://rruff.geo.arizona.edu/AMS/minerals/Clinocervantite "AMSCD Search Results"] American Mineralogist Crystal Structure Database It has a specific gravity of 6.72 and a molecular weight of 307.50 gm. It has a biaxial optical class.