Rock Identifier
Peridot (Olivine) (Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)) — mineral
mineral

Peridot (Olivine)

Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)

Hardness: 6.5–7 on the Mohs scale; Color: Lime, olive, or yellowish-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 3.2–4.3.

Hardness
6
Color
Lime, olive, or yellowish-green
Luster
Vitreous (glassy)
Identified More mineral

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Physical properties

Hardness: 6.5–7 on the Mohs scale; Color: Lime, olive, or yellowish-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 3.2–4.3.

Formation & geological history

Formed deep within the Earth's mantle and brought to the surface by volcanic activity in mafic or ultramafic igneous rocks. It is also found in pallasite meteorites. Geological age ranges from millions to billions of years depending on the deposit.

Uses & applications

Primary use is in jewelry as a gemstone. Industrial varieties are used as a refractory material, in sandblasting, and as a flux in steel production.

Geological facts

Peridot is one of the few gemstones that occurs in only one color. It has been found in meteorite debris and even on Mars, earning it the nickname 'the space gem.' It is the birthstone for August.

Field identification & locations

Identify in the field by its distinct olive-green color, lack of streak, and glass-like fracture. Common locations include Arizona (USA), Pakistan, Myanmar, and the Red Sea. Collectors look for high clarity and 'vibrant' green saturation.