Kegginite
Kegginite is a phosphate mineral discovered in Packrat mine near Gateway, Colorado. This specific mineral is very rare, and has only been found in one specific level of the Packrat mine. Kegginite is named as such due to the presence of the ε-isomer of the Keggin anion as the basis of the structural unit.[1] It also recognizes the work of J.F. Keggin[3] who first experimentally described the structure of the α-Keggin anions in 1934. At the time of its discovery it represented a new crystal structure type and was the first mineral discovered with a vanadyl-containing polyoxometalate anion.[2]