Peridot is the gem-quality variety of the mineral olivine, a magnesium iron silicate with the general formula (Mg,Fe)2SiO4. It’s one of the few gemstones that occurs only in green, its signature color.

Appearance & Properties

• Color: Olive green, yellowish-green, or brownish-green. The exact hue depends on iron content—more iron gives deeper greens.

• Luster: Vitreous (glassy).

• Transparency: Transparent to translucent.

• Crystal System: Orthorhombic.

• Hardness: 6.5–7 on the Mohs scale.

• Cleavage: Poor; fracture is conchoidal to uneven.

• Refractive Index: 1.64–1.70.

Occurrence

Peridot is typically found in:

• Volcanic rocks (basalts, peridotites, and xenoliths)

• Mantle-derived material brought to the surface by volcanic activity

• Pallasite meteorites (very rare!)

Major sources include:

• USA (Arizona)

• Myanmar (Burma)

• Pakistan

• China

• Vietnam

• Norway

• Egypt (historical mines on Zabargad Island)