Diopside is a pyroxene mineral composed of calcium magnesium silicate (CaMgSi₂O₆). It commonly forms in igneous and metamorphic rocks and appears in a variety of colors, including green, brown, yellow, and even violet. The most well-known variety is chrome diopside, which gets its vibrant green color from the presence of chromium. Diopside has a Mohs hardness of 5.5 to 6.5, making it moderately durable but best suited for jewelry with protective settings. Major sources of diopside include Russia, Pakistan, Italy, and the United States.