The GemHunter's Guide to Gold and Diamonds in Montana ...
Aug 12, 2013· Alnöites, monticellite peridotites, carbonaterich mica peridotites, monchiquites, lamproites, and kimberlites are all reported in Montana (these are all rare volcanic rocks that could have diamonds Erlich and Hausel, 2000).Many of these intrusives occur in the central Montana alkalic province in eastern Montana, which overlies the Wyoming Province (Hearn, 1989; Scambos, 1991).