Mineral Specimen and Product Inventory Search
- White Cap mine, Pennington Co., South Dakota, United States
- 5.5 x 3.5 x 2 cm - Sm Cabinet
It's not a crystal, more like a broken grain in Siderite matrix to 0.75mm. Olmsteadite is extremely rare. I have never self-collected one myself in the 40 plus years of tromping the Hills.