Minerals
Carlfriesite
carlfriesite
CaTe⁴⁺2Te⁶⁺O8
Carlfriesite Mineral Specimen For Sale — via www.dakotamatrix.com · Source
Overview
Carlfriesite is a rare tellurium mineral with the formula CaTe4+2Te6+O8, or more simplified: CaTe3O8. It has a Moh's hardness of 3.5 and it occurs in various shades of yellow, ranging from bright yellow to a light buttery color. It was named after Carl Fries Jr. (1910–1965) from the U.S. Geological Survey and the Geological Institute of the National University, Mexico City, Mexico. It was previously thought to have the chemical formula H4Ca(TeO3)3, but this was later refined.