Chromian Diopside, also known as the Cape Emerald, often yields gemstones that rival emerald in beauty but at a much lower cost. These gems are common in some kimberlite & lamprophyre pipes, but are often discarded when mining diamond pipes for diamond. Many gem-quality chromian diopsides were found in kimberlite in the Colorado-Wyoming State Line district and also in anthills and lamprophyres in the Cedar Mountain area of Wyoming.