Peridot: August Birthstone

Peridot used to be call Topazion because it was discovered on the Island of Topazios in the Red Sea. Today that island is known as Zebiret or the Isle of St. John.
In the eighteen century the mineral Topaz was officially given it's name and the gem form of Olivine was given the name Peridot.

Peridot is the official birthstone for the month of August as adopted by the American National Association of Jewelers in 1912.

How do you pronounce the word Peridot? Peridot has got to be the most mispronounced name of all common gemstones.

So is it pronounce

Pear-a-doh
Pear-a-doe
Pear-i-doh
Pear-i-doe
pear-a-dot
Per-i-dot
Per-e-doh
Per-a-doh
Pear-e-dot

The correct pronunciation is actually per'i-dot however some dictionaries list the correct pronunciation as pear-a-doe.

According to legends you will be protected from evil if you wear peridot.

With their rich green color and a hint of yellow Peridot has often been mistaken for Emeralds.
Some of Cleopatra's famous Emeralds were actually Peridot.

Peridot has been mined for more then 3500 years. The oldest known mine is St. John's Island, Egypt in the Red Sea.
Today most Peridot comes from China, Brazil, Kenya, Norway and new mines in Afghanistan and Pakistan.

Peridot Chemical composition: (MgFe)2SiO4
Class: nesosilicate
Crystal system: orthorhombic; 2/m2/m2/m
Crystal habit: commonly as compact or granular masses, also as loose or embedded grains, sometimes in volcanic nodules. Crystals are rare, usually as vertically striated prisms.
Twinning: twinning is uncommon, simple twinning can occur on {100}, {011}, and {012}. Cyclic twinning on {031} reportedly produces trillings.
Specific gravity: 3.22 - 3.45, increases with iron content
Index of refraction: 1.65 - 1.69, increases with iron content
Birefringence: strong, (0.035 - 0.038)
Pleochroism: weak; pale yellow-green to yellow/pale yellow-green to yellow/yellow to yellow orange
Hardness: 6.5 to 7, hardness increases with magnesium content
Color: olive green, green, yellow, brown
Luster: vitreous to oily
Transparency: transparent to translucent
Cleavage: poor on {010} and {110}, {010} cleavage improves with increasing iron content
Fracture: conchoidal
Streak: colorless

Peridot is the gemstone for the 16th wedding anniversary

Other birthstone for the month of August are
Alexandrite, Carnelian, Diamond, Sapphire, Sardonyx and Ruby.

The Zodiac signs of Leo and Virgo both fall in the month of August.
Leo Jul. 23-Aug. 23 and Virgo Aug. 24-Sep.22
Stone associated with Leo and Virgo are Citrine, Jade, Jasper, Onyx, Tourmaline, and Zircon

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