NEW FIND IN THE SOUTH DAKOTA PEGMATITES

Between 2002 and 2005 I took several trips to collect in the Black Hills of South Dakota, specifically in the many pegmatite localities near Custer and Keystone. At the Nickel Plate Mine, near Keystone, the locality in which the mineral arrojadite was first discovered, we spent much time digging through the tailings looking for examples of this mineral. We were rewarded by much arrojadite, some in large cleavable masses up to several pounds each, and measuring several inches across; we also found other phosphates, cassiterite, and discovered two minerals not reported from here previously: first, tapiolite, which was identified by x-ray diffraction at Montana Tech, and ferrocolumbite, which was far easier to identify by habit, morphology, luster, color, hardness, etc.

At the famous Tip Top Mine we found numerous phosphates and other curious minerals, but we found a fist-sized mass of reddish phosphate originally thought to be hureaulite, but on x-ray diffraction identified it as triploidite. This mineral has yet to be found at this locality.

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