Diopside often occurs as a bright green, translucent to transparent gem that is cut into faceted stones, cabochons, and beads. Its green color is often bright enough that it is used as a substitute for emerald. A rare variety of diopside known as “star diopside” contains fine prismatic crystals of magnetite. When polished en cabochon, they display a silver four-ray star. The property of displaying a star is known as “asterism”.

Diopside has potential uses in ceramics, glass-making, biomaterials, nuclear waste immobilization, and fuel cell technology. Unfortunately, natural diopside is rarely found in deposits that simultaneously have a size, purity, and location that allows economic mining. This makes synthetic diopside cost-competitive with diopside produced by mining.