Description: Emerald is a precious gemstone and a green variety of the mineral beryl. • Mineral family: Beryl • Hardness: 7.5–8 on the Mohs scale • Luster: Vitreous (glassy) • Transparency: Transparent to translucent Key points: • Emeralds almost always contain natural inclusions called “jardin” (garden-like patterns). • Because of these inclusions, emerald is softer in practice than its hardness suggests.