Peridot

(August Birthstone)

The name olivine is from the Latin oliva in reference to the mineral's
color. Peridot is from a thirteenth century English word peridote.
Peridot (pronounced pear-uh-doe) is the gem variety of olivine. The
olivine's are isomorphous (all have the same crystal structure), with
varying chemical compositions. Olivine, which is actually not an
official mineral, is composed of two minerals: fayalite and forsterite.
Fayalite is the iron rich member with a pure formula of Fe2SiO4.
Forsterite is the magnesium rich member with a pure formula of Mg2SiO4.
Olivine's formula is written as (Mg, Fe)2SiO4 to show the substitution
of the magnesium and iron. Peridot is usually closer to forsterite than
fayalite in composition although iron is the coloring agent for peridot.

The green color of peridot, the gem variety of olivine, is mainly
dependent on the amount of ferrous iron present, this color then being
modified by trace amounts of Fe3+, Ti4+ and Ni2+. The better green
colors occur with a Fe:Mg ratio of about 1:8. Higher concentrations of
Fe result in less desirable yellow-green or brownish green shades. Pure
brown peridots are more rare. Peridot gems have a hardness of about 6.5,
which makes them very suitable for use as gemstones in earrings,
brooches and pendants. Their use as ring stones requires some extra care
to prevent abrasion and loss of polish.

Gem quality peridot comes from the ancient source of Zagbargad
(Zebirget) Island in the Red Sea off the coast of Egypt; Mogok, Myanmar
(formerly known as Burma); Kohistan, Pakistan; Minas Gerais, Brazil;
Eifel, Germany; Chihuahua, Mexico; Ethiopia; Australia; Peridot Mesa,
San Carlos Apache Reservation, Gila County, Arizona and Salt Lake
Crater, Oahu, Hawaii, USA. The best quality peridot has historically
come either from Myanmar or Egypt. But new sources in Pakistan are
challenging that claim with some exceptional specimens. The Arizona gem
material is of lesser quality, but is far more abundant and is therefore
much more affordable. An estimated 80 - 95% of all world production of
peridot comes from Arizona. The Myanmar, Pakistani and Egyptian gems are
rarer and of better quality and thus quite valuable approaching the per
carat values of top gemstones. Possibly the most unusual peridot is that
which comes from iron-nickel meteorites called p! allasites. Some are
actually faceted and set in jewelry.

The stone ranges in color from light yellow-green to the intense bright
green of new grass to olive. Because of the way peridot splits and bends
the rays of light passing through it, it has a velvety, "sleepy"
appearance-a shining rich glow. Throughout time, peridot has been
confused with many other gemstones, even emerald. Many "emeralds" of
royal treasures have turned out to be peridots! And although peridot is
distinctly a different shade of green, many jewelers refer to peridot as
"evening emerald". Emerald is a dark green as opposed to a yellow green
and always contains inclusions.

Other green gemstones confused with peridot include apatite (which is
much softer); green garnets (have no double refraction), green
tourmaline and green sinhalite (both of which are strongly pleochroic),
moldavites (no double refraction) and green zircon (significantly
heavier). All of these gemstones rarely have as nice a yellow component
to their green color as does most peridot, bu t! darker green peridot
can be confusing when good crystal form is not discernible.

Possibly the most unusual peridot is that which comes from meteorites
called pallasites. Some have even been faceted and set in jewelry, the
only extraterrestrial gemstones known to man.

Peridot is occasionally treated with colorless oil, wax, natural and
synthetic unhardened resins into voids to improve appearance. Surface
fractures are sometimes filled with a colorless hardened substance.

Due to its relative softness, peridot jewelry should get special care
and handling. Peridot is susceptible to attack by acids, particularly
hyrdochloric and sulphuric acids that are commonly found at the
jeweler's bench. These acids will remove a stone's polish surprisingly
fast. Quick temperature changes should be avoided.

As a gemstone, clarity is very important with peridot. Tiny inclusions
that are not singly visible to the unaided eye can nonetheless in
quantity impart a "sleepy" or hazy quality to the stone, and make the
color, however slightly, more brownish (not desirable). Peridot is used
as a gemstone. Mg-rich olivine is used in refractory sand and brick in
the casting industry because of its high melting point.

Peridot is not in such demand that imitators are rampant. However,
practically any transparent green material, natural or manmade, could
imitate peridot. Even until recently have jewelers used the term
"chrysolite" (latin for golden stone) in referring to peridot gems for
some reason.

Variety of:

Olivine

Hardness:

6.5 - 7 hardness increases with magnesium coontent

Chemical Composition:

(MgFe)2SiO4

History:

Peridot has been mined as a gemstone for an estimated four thousand
years or better, and is mentioned in the Bible under the Hebrew name of
pitdah.

Archaeologists have found valuable peridots in Alexandria, Egypt, which
must have come from the original source, the island of Zebargad
(zebargad being the Arabic word for peridot). It is located about 50
miles from the coast of Egypt in the Red Sea. Faceted stones have also
been found in the ruins of ancient Greece and attributed to the same
source.

Zebargad, which was known for many years as Saint John's Island, may
have been mined as early as 1500 BC The island was discussed in the
natural history of Pliny the Elder (23-79 A.D.) as having been explored
in the fourth century BC it was called "the Serpent Isle' " since its
many poisonous snakes interfered with mining activity. Eventually, an
Egyptian ruler had the snakes killed and kept the miners isolated at
work on the island. Because the rich green stones were so coveted,
guards of the deposits were told to kill any unauthorized travelers
approaching the island.

The Greeks and Romans referred to peridot as topazion and topazius
respectively and this name was later given to topaz, to end the
confusion with the two gems.

Peridot was quite popular during the baroque era. It was originally
introduced to Europe by the Crusaders during the Middle Ages, and was
used for ecclesiastical purposes.

The largest known faceted peridot (310 carats) is displayed at the
Smithsonian Institution, Washington, D.C. Now a part of the Diamond
Treasury in Moscow, Russia, is a yellowish-green 192.75-carat stone that
belonged to the czars. A step-cut peridot of 146 carats is in the
Geological Museum, London, England. The collections of the American
Museum of Natural History in New York and the Chicago Museum of Natural
History have included beautiful examples of peridot. Many peridots were
taken to Europe by crusaders returning from the East and kept in
cathedrals. Especially fine specimens are in the Cathedral in Cologne.

Peridot was positively identified on comet Hale-Bopp.

Lore:

Some think that the "emeralds" worn by Cleopatra were actually peridot.
Similarly, a large stone at the shrine of the Three Holy Kings at
Cologne was thought to be an emerald until correctly identified as a
peridot in the late 1800s.

Ancient Egyptians called peridot "the gem of the sun," although they
believed its seekers might not find it in sunlight. Because of their
brightness in the desert sun, the stones were supposedly invisible by
daylight. In darkness, however, they were alleged to give off a light of
their own. By night, miners were said to mark their locations
accordingly and return to recover their treasures by day. 

Peridot was believed to have the power to dissolve enchantments.
Pirate's believed peridot had the power to drive away evil spirits (and
the night's terrors), especially if set in gold. But as protection from
evil spirits it must be pierced, strung on donkey hair and worn on the
left arm.

As a medical remedy, it was powdered to cure asthma. Holding a peridot
under the tongue was supposed to lessen the thirst of a person suffering
from fever.

The high priest's breastplate, which is described in the Biblical book
of Exodus, includes a stone for each of the twelve tribes of Israel, one
being peridot. The Bible also tells of a jewel worn by King Esekiel from
Exodus, an impressive peridot.

Hawaiian natives believe peridot is the goddess Pele's tears. The
Ottoman Sultans who gathered the largest collection during their
600-year reign from 1300-1918, with an impressive array of both loose
gem stones as well as peridot earrings, peridot rings and other peridot
jewelry.

Metaphysical:

Peridot is said to bring healing and vitality to the whole body. It is
also said to increase patience, confidence and assertiveness.

Peridot is said to help slow the aging process, physically and mentally.
It is also said to be helpful in facilitating the birthing process.

Peridot helps stimulate growth. The brighter, and more yellow the color,
the more intense the experience. This is the stone of adventure. We
never know what we will find, but it sure is a heck of a ride!

If you want to start a growth period, meditate with peridot in your left
hand (the receiving one). Visualize the bright color (and the energy
that accompanies it) coursing through your chakras, clearing and
grounding them. Then see it clearing and grounding your aura. Tell the
universe that you are ready for growth, and trust the universe to do the
rest. It's ok to then visualize your chakras returning to their normal
colors, it is just more intense this way!

source: Teresa`s Rock of the Week Newsletter