Caldasite (Caldasite Caldasite) is a very rare uraniferous zirconium ore, composed of ZrSiO4, ZrO2 (baddeleyite; over 60%), and U3O8. This complex ore is primarily found in the region of Pocos De Caldas, Minas Gerais, Brazil (hence the name caldasite). Caldasite is very heavy and is mostly ashy in color, usually varying between green, brown, and r...