Little-known hetaerolite is a secondary mineral associated with other manganese minerals, primarily in hydrothermal ore deposits. Interestingly, its type locality is Franklin, the only locality that could rival Bisbee (where this is from) as "the" great American mineral locality. This is an extremely rich specimen, with the hetaerolite piled up in stalactitic form 2.5 cm thick on the matrix. Ex. Dave Stoudt collection, and in an older collection before that in the early 1950s. But the specimen may be much, much older. From the 1900 Level.