- Montgomeryite with Whitlockite-Bobdownsite
- Miniature, 5.4 x 3.4 x 1.4 cm
- Tip Top mine (Tip Top pegmatite), Fourmile, Custer Co., South Dakota, USA
Montgomeryite is a rare phosphate and the Tip Top pegmatite has produced the world's best and most colorful specimens bar none. Captivating, red-orange, lustrous montgomeryite crystals cover both sides of this piece and colorless to white, translucent to transparent rhombs of whitlockite-bobdownsite provide contrast and additional interest to this specimen! On the reverse side there are small, black-brown patches beneath the phosphates that aren't readily identifiable, but could be todorokite or robertsite. Montgomeryite is a hydrated calcium magnesium aluminum phosphate. An exceptional and rich piece of these rare phosphates from this well-known secondary phosphate locale that hasn't produced any specimens since the late 1980's and the pit is now filled with water. Collected in the 1980s. We will probably never see this material again, and it is not only world's best of species, but is truly one of the most beautiful minerals you will ever look at under a scope.