Montgomeryite

Item Description

This is a very important piece from Tip Top Mine near Custer, South Dakota, where Tom Campbell (from whose collection this comes) and others reported the first pegmatite occurrence of Montgomeryite and it was very notable because of the intense, bright red color of the crystals as in this piece. Dozens of small clusters of vibrant red Montgomeryite dot the surface of a large shard of pink Microcline feldspar and are associated with finely crystalline, white Englishite and charcoal-black Todorokite and green Mitridatite; a collection of rare and colorful secondary phosphate species! Montgomeryite is a hydrated calcium-magnesium-aluminum phosphate and prior to this find in the 1980s was previously known only from sedimentary phosphate occurrences. The Individual, bright red, lustrous Montgomeryite crystals that compose the clusters are from 0.2 to 1 mm in length and contrast well with the other phosphates, the microcline and the Todorokite. This piece happens to be very significant in that is one of the original pieces collected by Campbell upon which he performed the original characterization and determined the optical properties when the (new for the species) occurrence was described in the Mineralogical Record, v. 14, no. 3, pp. 195-197 in 1986. This piece was given to Bill Roberts as a mentor by Campbell , and has the former collection number #2784 of Bill Roberts on the piece. A very significant and colorful piece with impeccable provenance. Ex Tom Campbell collection (by the way, Tom is in addition to being a solid mineral collector, a coauthor on the old huge book set Encyclopedia of Minerals). This little rarity is the highlight of this auction set, and actually it is very rich and not "so little" after all when you look at how rare this material is in quality. Valued $2500 or more. Things like this have not been on the market since the dispersal (by us) of the important South Dakota phosphate Barlow collection in 1998, and then the Korpi collection (which had much of Barlow's TipTop suite he had purchased from us) in the early 2000s. These are one of the most beautiful of American microminerals, and the specimen is big enough to be a fine display piece by any standard.