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crystals,
gems and minerals
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Peridot
(August Birthstone)
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Scientific:
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. |

This peridot specimen has a matrix of white
clay mixed with in with massive peridot.
This specimen was discovered in 1997 at the
Datso Mine in Pakistan.
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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
pallasites. Some are actually facetted 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, but darker green
peridot can be confusing when good crystal
form is not discernible. |

This beautifully fashioned "modified Emerald
Cut" is faceted from a rare piece of
Norwegian peridot. The stone contains some
small inclusions just visible upon very
close inspection.
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Possibly
the most unusual peridot is that which comes
from meteorites called pallasites. Some have
even been facetted 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. |

Forsterite (variety peridot) from the
Smithsonian Institute © Chip Clark,
Smithsonian National Museum of Natural
History
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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 refering to
peridot gems for some reason.
Variety of: Olivine
Chemical Composition: (MgFe)2SiO4
Hardness: 6.5 - 7 hardness increases with
magnesium content |

Forsterite (variety peridot) from the
Smithsonian Institute © Charles Vega,
Smithsonian National Museum of Natural
History
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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 beautiful peridot gemstone in this
pendant was faceted from natural peridot
rough mined on the San Carlos Indian
Reservation in Arizona, USA.
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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. |

Photo courtesy of
Dave's Down To Earth Rock Shop
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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. |

Chipped bead necklace courtesy of a Private
Collector
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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! |
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Teresa's Rock of the Week, formerly Gail's Rock of the Week |
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