This native crystal formation is from the Northwestern Mine in Central, Keweenaw County, Michigan, USA. This was a copper mine that operated in the mid 1800’s. All work ceased in 1865 and it was absorbed by the Central Mining Company. It contained 12 different minerals including silver. This interesting formation has a cross-like structure made up of complex pseudo-cubic crystals. It measures approximately 2 1/8 x 1 1/8 x 15/16 inches or 53 x 28 x 24 mm.