PERIDOT

A peridot and diamond ring by Bailey, Banks & Biddle

Species:  Peridot
​​Mohs Hardness:  6.5 to 7 out of 10
Color:  Yellowish green to greenish yellow to brownish green.
RI:  1.654 to 1.690 (+/-0.020)
Birefringence:  0.035 to 0.038 (usually 0.036)
SR/DR/AGG:  DR
Clarity Type:  Type II
Optic Character:  Biaxial positive or negative (common point is usually halfway between the 2 extremes)
Pleochroism:  Weak yellow-green and green, only noticeable in dark stones.
Spectrum:  Strong, narrow bands at 453, 477 & 497nm.
Fluorescence:  Inert
SG:  3.34 (+0.04 / -0.07)
Routine Treatments:  None

PERIDOT FACTS

Peridot has noticable "doubling" when viewed under magnification.

Peridot is a very attractive greenish yellow to yellowish green gem.

​Ancient Egyptians called peridot "the gem of the sun".​

Some peridot dates as far back as 4.5 billion years ago, being found in pallasite meteorites.

In 2005, peridot was found in comet dust brought back from a robotic space probe.

Due to its relatively high birefringence, peridot can display visible doubling.

Peridot is an August birthstone and is the 15th wedding anniversary gemstone.​

PERIDOT GALLERY

All photos courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA)