Unlike other green stones, peridothas had its ups and downs throughout history. After a dazzling start in 1500 BCE, peridot fell out of favor when the emerald appeared in the sixteenth century,e and rose to fame again at the beginning of the twentieth.e. Today, it is a fine stone appreciated by many.
History
The story of peridot begins off the coast of Egypt, on an island in the Red Sea, the island of Zebirguet. Even though it is only 4.5 square kilometres in size and rises to an altitude of 235 m with Mont-Péridot, Zebirguet is inseparable from peridot.
Peridot arrived in Europe in the Middle Ages thanks to the Crusades. It was at this time that Zebirguet was renamed « Ile St-Jean » and the new stone was named « "Crusader Emerald" ». It was used in the making of many pieces of religious goldsmithing.
The appearance of emeralds in the sixteenthe century caused a sharp drop in the popularity of peridot. In the seventeenth century,e, jewellers used to say « he who has two peridots has too many! ».
Characteristics of peridot
Peridot is a green idiochromatic stone, ,that is, the chemical element responsible for its colour (Fe iron) is always present in its chemical composition. It does not exist in any other colour. Peridot has a vitreous lustre, and sometimes showcases chatoyancy (cat’s eye effect), or in rare cases asterism (star effect).
The typical diagnostic inclusion in peridot is a chromite crystal with a circular fracture surrounding it known as a « lily pad ». It is also possible to observe the doubling of facet edges under high magnification. This is not an inclusion, but rather an optical characteristics of certain stones which may help in identification.
There is no synthetic peridot. Peridot is commonly imitated with fabricated glass and assembled stones such as doublets and triplets.
The optical and physical properties of two stones in particular approximate those of peridot. These are sinhalite (discovered in Sri Lanka), which is more of a collector's stone, and diopside, which is increasingly being found in the trade. Peridot can also be confused with any green-yellow stones. For example, yellow chrysoberyl, yellow-green sapphire, zircon, sphene, demantoid garnet, tourmaline, apatite, and fluorite.
For the bench jeweller, peridot can be scratched and abraded easily with a metal file. It is sensitive to heat and thermal shock, as well as acids, and must be protected during repairs.
At the time of sale, the customer should be warned of the fragility of the stone to sudden changes in temperature as well as acids; The stone may need to be repolished after several years of use.