Wyoming's Leucite Hills include a group of rare lamproitic volcanic flows, flow breccias and volcanic necks known as lamproites. These potassium-rich volcanics contain a variety of unusual minerals including gem-quality peridot first recognized in 1997. Microscopic minerals in these rocks include leucite, ricterite, armalcolite, magesiochromite, noonkanbahite, and jadeite to name a few.