Peridot Jewelery

The chemistry of peridot
Peridot is a semi-precious stone that is cut from gem quality forsteritic olivine. Olivine derives its name from the characteristic green hue of the mineral. The forsteritic subtype of olivine is composed mainly of magnesium and produces the more highly valued luminescent lime-green color in peridot. Iron is also present in olivine. Depending on the predominance of iron over magnesium, the peridot gem assumes an increasingly golden hue, finally to become pure brown or gold at the other end of the olivine spectrum. This subtype of the mineral is called fayalite olivine and it contains very little magnesium.

Where is peridot mined?
Among the most ancient gem stones, references to the stone are made in the Bible. Some authorities even suspect that the famed emerald mines of Cleopatra were really peridot mines. Whatever the case, peridot seems to have been a great favorite of ancient Egyptian royalty who habitually paid for huge quantities of the stone from an island in the Red Sea which is called variously as St. John's Island, Zabargad or Zebirget. In recent times, other locations have yielded peridot stones with different grades and colors.

Peridots with lime green color are most often found in Pakistan, Burma and Zabargad. The mines in Pakistan were only recently discovered but they yield some of the highest grades of this gem stone. Bluish green peridots are found mostly in Burma while yellowish peridots are mined in the USA and China. Brazilian peridot is characteristically light or yellow green in color. The world's largest supplier of peridot is held to be Peridot Mesa located in Arizona where, it seems, the native Indians had been using peridot charms and jewelry for a long time. Peridot has also been found embedded in metallic ore in Pallasite meteorites and is apparently also abundant in other planets, such as Mars.

Although peridot stones are not difficult to come by, gem-quality items are rather rare.

The physical properties of peridot
As a crystal, peridot has a hardness of 6.5 to 7 on the Mohs scale of hardness. This means that although it is suitable for making into a gem stone, it is not particularly resistant to abrasion. It is softer that garnet, for instance. Its hardness can be compared to that of a quartz crystal. As mentioned, peridot is typically of a green hue. Because of this, the relatively rare brown peridots, some of which may be of exceptional clarity and very brilliant luminosity make very elegant and unique pieces of jewelry. Typically, the stone is found in sizes of from 2 to 7 carats. However, in Burma and Pakistan, larger carat samples are not unusual. It should be noted that peridot is unique among the softer gem stones in that it is considered tastefully correct to set it in 14 carat or more gold and platinum as well as to use diamonds with it.