silicates
Peridot
- Also known as
- olivinechrysoliteevening emerald
- Crystal system
- orthorhombic
- Hardness
- 6.5–7 on the Mohs scale
- Lustre
- vitreous
- Colour
- Yellow-green to olive green
- Where it forms
- In the earth’s mantle. Olivine is the dominant mineral of the upper mantle, and peridot reaches the surface in basalt and in mantle fragments carried up by eruptions.
- Chiefly from
- Zabargad, EgyptArizona, United StatesPakistanMyanmar
Why it is that colour
Iron, and unusually it is the iron itself rather than a trace impurity — olivine is a magnesium-iron silicate and the green is intrinsic. Peridot is one of very few gems that occurs in only one colour.
Safety
Safe to handle. It is sensitive to acid and to thermal shock, so it should not be cleaned ultrasonically.
Where it comes from
Arizona’s San Carlos Apache reservation supplies a large share of world peridot, mined by tribal members. Pakistani material from Kohistan is high quality. Zabargad is worked out.
Historical use
One of the few gems found in meteorites: pallasites are stony-iron meteorites with olivine crystals embedded in a nickel-iron matrix, and gem-quality extraterrestrial peridot has been cut from them.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Mined on the Egyptian island of Zabargad in the Red Sea from at least 1500 BC, and the classical topazios almost certainly refers to this rather than to modern topaz. Ancient sources associate it with the sun and with protection against night terrors. Much of the emerald in medieval European church treasuries — including, reportedly, in Cologne Cathedral — turns out to be peridot.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Sold as this, but not
Worth knowing
Peridot is mantle rock you can wear. Olivine makes up most of the earth's upper mantle, and a peridot crystal is a sample of the layer beneath the crust, brought up by an eruption. There is a great deal more of it than of anything else in this collection — it just happens to be several tens of kilometres down.
Pallasite meteorites are the other source, and they are among the most beautiful objects in any collection: olivine crystals suspended in a metal matrix, thought to come from the boundary between the core and mantle of a shattered asteroid. Cut into slices and lit from behind, they glow.
Identity checked against IMA-CNMNC master list, June 2025.