These native copper crystals are from the Northwestern Mine in Central, Keweenaw County, Michigan, USA. This mine operated in the mid 1800’s for the recovery of copper. It was later incorporated into the Central Mine. It contained 12 different minerals including copper. This interesting formation features 3 arborescent branches of well defined crystals originating from a central point. It measures approximately 2 15/16 x 1 1/4 x 3/8 inches or 75 x 32 x 9 mm.