Peridot

Egyptians mined peridot on Zabargad island (today Shatiyah) in the Red Sea over 3,500 years ago — this location is one of the oldest gem mines in the world. Ancient Egyptians called it "the stone of the sun" and believed it prevented the darkness of night; they wore it in gold settings for protection.

Romans called peridot "topaz" (the origin of later confusion between various stones in antiquity). Ancient descriptions of "emeralds" in Cleopatra's collection were likely peridots — Egypt was a source of both.

Zabargad island was lost to the Western world for 1,500 years and rediscovered in the 19th century. Today it is administered by the Egyptian government, but the mine is mostly inactive. Modern commercial peridot mining takes place in Pakistan and the Arizona reservation.

Geological origin: Peridot forms in the Earth's mantle at high temperature and pressure — brought up by volcanic activity. Found in mafic and ultramafic igneous rocks (basalt, kimberlite). Hawaiian volcanic sand contains microscopic peridot beads (olivine is a common mantle mineral).

Meteorites and space: Peridot has been discovered in pallasite meteorites (metallic meteorites with olivine crystals). Asteroid Ryugu, analyzed by Japan's Hayabusa2 probe, contains olivine. The mineral is one of the most common in the solar system.

Cleopatra and Zabargad: Egyptian Zabargad Island (St. John's Island) in the Red Sea has been a peridot mining site for 3,500 years BC. Ancient Egyptians called it "the stone of the sun." As peridot and emerald colors were confused in antiquity (both green), a theory exists that Cleopatra wore peridots.

Pakistani peridot: The high mountains of Kaghan Valley (above 4000m) in Pakistan produce some of the finest modern peridot crystals — olive green to vivid yellow-green with excellent transparency. Specimens are often larger and more intensely green than San Carlos stones.

San Carlos peridot: The deposit on the Apache Indian Reservation in Arizona, USA, is a leading source. Smaller stones (typically under 5 ct) with excellent color.

Peridot is relatively common in accessible carat weights (Arizona, China, Egypt — Zabargad island), but high-quality stones with intense olive green color and clarity above 5 ct are rarer.

Pakistani peridot from the Himalayan mountains (above 4,500 m elevation) yields crystals from which stones above 50 ct can be cut — such specimens are prized among collectors. Arizona (San Carlos Reservation, Apache) is the largest commercial source but typically for stones under 1 ct.

A distinction unique among all gems: peridot has been found in meteorites — particularly in pallasite meteorites, where olivine (the mineral of peridot) forms crystals within a metallic matrix. Such "meteoric peridot" is an exceptionally rare collector's item.

Peridot is one of the few gems that comes in only one color — olive green. Color intensity depends on iron content: more Fe = darker, more olivine color; less Fe = lighter, more yellowish. Color cannot be changed by heat treatment.

Meteoritic peridot (from pallasite meteorites) is the only gem that does not originate on Earth. Pallasites are an exceptionally rare type of meteorite (only ~1% of all falls) and contain olivine crystals in nickel iron. These crystals per GIA were part of the cosmos before Earth existed.

Peridot can dissolve in hydrochloric acid (HCl) — a unique property among precious stones. The acid test is one way to distinguish it from imitators, although this method destroys the stone.