• It is a birthstone for November (as is citrine) and the state gem of Texas. TOPAZ DEPOSITS Topaz is an aluminum silicate containing fluorine and has a chemical formula of A l2(F,OH)2SiO4. It is formed by fluorine- bearing vapours given off during the las t stages of the crystallization of igneo us rocks. It typically occurs in cavitie s in rhyolites and granite, in pegmatite dikes, and in high-temperature veins. Of ten associated with cassiterite, topaz m ay be useful to indicate the presence of that tin ore.
Transcript
• It is a birthstone for November (as is citrine) and the state gem of Texas.
TOPAZ DEPOSITS
Topaz is an aluminum silicate containing fluorine and has a chemical formula of Al2(F,OH)2SiO4. It is formed by fluorine-bearing vapours given off during the last stages of the crystallization of igneous rocks. It typically occurs in cavities in rhyolites and granite, in pegmatite dikes, and in high-temperature veins. Often associated with cassiterite, topaz may be useful to indicate the presence of that tin ore.
The finest British topaz is found in the Cairngorm Mountains in the Central Highlands, especially at Ben a Buird, Scotland. The famous topaz rock of the Schneckenstein, in Germany, yields pale yellow crystals that were formerly cut for jewelry. Fine topaz occurs at several localities in the Urals and in Siberia, Russia, and beautiful crystals come from Takayama and Tanokamiyama in Japan. Brazil is a famous locality, the well-known sherry-yellow crystals coming from Ouro Preto, Minas Gerais, where they occur in a kaolinitic matrix. In the United States fine topaz has been worked near Pikes Peak, Colo., and in San Diego county, Calif. Common topaz occurs in coarse crystals at many localities.
• Most of the worlds production; from pegmatites • Imperial Topaz (worlds only source),sherry-colored, yellow and blue • Sherry-colored is heated to produce pink • Most (if not all) Brazilian blue topaz has be treated to enhance or alter the original color.
Brazil
(Minas Gerais, near Ouro Preto)
Imperial Topaz: favorite among favorites! The C zar¹s gem, originally discovered a hundred year
s ago in the Ural Mountains of Russia, the very r are Imperial Topaz was so coveted that it was s
trictly reserved for the Czar and his family. That location, however, has long been exhausted. Th
e only working Imperial Topaz mine in the world is the Capao Mine near Ouro Preto, Brazil. This
beautiful gemstone ranges in colour from golde n to peach to salmon with sherry reds, pink and
purples as the most sought after shades.
Ouro Preto
http://www.liccini.com/Preview/PreviewCover.html
Areas surrounding Capao Imperial Topaz Mine
http://www.liccini.com/Preview/PreviewCover.html
2000 acres man-made lake to sluice crystals
Mine face
Camp
http://www.liccini.com/Preview/PreviewCover.html
The Capão Mine, in the Ouro Pretoregion of Minas Gerais State.
Imperial Topaz Crystals from Ouro Preto
http://www.liccini.com/Preview/PreviewCover.html
Mexico, near San Luis Potosi
• Significant source; in cavities in rhyolitic volcanic rocks • Most very pale pink to colorless, or sherry-brown • Some more deeply colored stones are known to fade in sunlight
Durango, Mexico
Location of mineral deposit: Mogok, Mandalay Division, Bur
ma.Description: Well crystallized
- water clear colorless topaz crys tal 6 cm long with complex ter
mination. Theterminationshows t he t ypi cal t r i angul argrowthpat t er ns and i s ver y l ust r o us. Thecr yst al has a smal l al bi t e inclusionon one edge and has cont act o nr ear .
Overall size of mineral specimen: 6x2.5x2 cm.
BURMESE TOPAZ
Sri Lanka
• Mined from same gem gravels that produce corundum• Mostly pale to dark yellow, colorless or pale green
U.S.A (minor production)
• Fine blue from Pikes Peak, CO (pegmatites) • Pale brown to colorless, Thomas Mts., Utah (volcanic rocks) • Pale blue to colorless, Mason Co.(near Streeter), TX (pegmatites) • Also scattered pegmatites in NH, ME, SC, CA
Gem-grade peridot is usually close to the Mg end-member (12-15% Fe2SiO4 present) of olivine; the Fe present is a chromophore that gives a dark or medium yellowish-green color. Some of the best, brightest green peridot contains traces of Ni or Cr, which are also chromophores. Peridot is a birthstone for August, along with sardonyx. The name Chrysolite is an older German name that was once applied to all gem olivine; the term is not as commonly used today but is sometimes used to denote a more yellowish-green to greenish-yellow stone, as opposed to a dark yellow-green or brownish green (olive green) common to peridot. Peridot is sometimes also referred to by jewelers as "evening emerald".
1 .8 2 ct.
ccc153
0 .8 7 .ct
3 09. ct.http://www.gemhut.com/peridot.htm
Peridot is restricted in occurrence to metamorphosed impure dolomites and to basic or ultrabasic (low in Si, high in Mg and Fe) igneous rocks. Nearly all gem peridot is derived from the latter. Unlike most other gems, olivine is highly susceptible to chemical weathering and thus does not survive very long at the surface in wet climates. This fact probably accounts for the very limited number of known gem localities, and their restriction to areas having arid or semi-arid climates. Most gem peridot, in fact, has its source from three localities: Zagbargad Island (also know as St. Johns Island) in the Red Sea; Myanmar (Burma); and Arizona.
Archaeologists have found valuable peridots in Alexandria, Egypt, which must have come from the original source, the island of Zagbargad (zebargad being the Arabic word for peridot). It is located about 50 miles from the coast of Egypt in the Red Sea. 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.
EGYPT’S PERIDOT DEPOSITS
Zagbargad Island (Egypt),
• In veins that cut ultramafic rock (peridotite, dunite) • Mines originally worked by primitive methods; were improved prior to W.W.I. $2 million mined in 4 year period preceding W.W.I.• Mines nationalized in 1958.• Little or no mining currently taking place.
See P.C.Keller5 (1990)
Peridot Mesa, San Carlos Apache Reservation, Gila Co., Arizona.Until very recently, 80-95% of world peridot production was from this locality .From ultramafic nodules in basalt; small, granular crystals Exclusive mining rights held by various Apache families .Inclusions include glass blebs, chromite in "lotus leaf" habit. Crystals typically small (1/4-1/2"), yielding gems of 2 carats or less. Gems over 5 carats rare.
UNITED STATES’S PERIDOT DEPOSITS
San Carlos, Arizona
A view looking north toward the l- ow lying edge of Peridot Mesa This deposit is on the Apache Indian Reserva
tion and is mined by free lance tribal miners.c cccccc Mesa is comprised of a huge
basalt flow
containing fractured masses of olivine. As m uch as 20 percent of the volume of the flow c
onsists of shattered peridot . Primarily by use of hand tools , tribal miners break the basalt/
olivine rock and screen out the larger fragme nts of gem material. Most of these fragments are rather small (<5 ct.) and are tumble polis hed and used as beads.
http://www.mtlilygems.com/gemndx.html
Apache Nation Peridot Mesa is a community owned and operated deposit. Local miners and families use the resource to meet everyday living expenses. Seen as a gift from the creator the Mesa is highly regarded and protected in the community. Mining seasons are spring to early summer and fall winter seasons. "Jackpots" are what are known as larger pockets of the elusive gemstone.
Looking into the canyon at the northern end of Peridot Mesa
Many areas of Per idot Mesa have be
en mined for gem material. The gem
- bearing layer of t he basalt varies fr om 3 to 35 meters
in thickness and c onsists of
shattered masses of ol i vi ne
encased in a vesi cular basalt. The c
anyon at the nort hern end of the m
esa has provided r elatively easy acc
ess to the gem zo ne and has been h
eavily worked. So me heavy equipm
ent, drilling, and blasting are being
used to get to this zone, but most of
the mining is still done by hand.
The olivine-rich zone in the vesicular basalt
- Portions of the olivine rich zone of the b asalt consist of up to 50 percent peridot.
The peridot masses are irregular in shap e and consist of tiny grains of shattered
peridot. Well over 90 percent of the peri dot is so small in size that it is of no valu
e as gem material. Occasionally, small s ections of the peridot masses are less sh attered and yield fragments large enoug
h to facet.
With luck, the tribal m iners come across peri
dot inclusions thatco ntain relatively large a
nd unshattered fragm ents of gemmy perido
t. The basaltwas brok en by hand and scree
ned out for gem mater ials. Blasting the rock i
n the gem zone would only further shatter th
e desired material. It i s estimated that the u
seful peridot fragment s represent less than
1 % of the total olivin ethat has tobe broke nf ree andscreened!G
emroughi s avai l abl e for purchase f rom
local miners or brokers.
Peridot from the San Carlos reservation can only be mined by tribal members. Because of the system by which the peridot is mined, gem rough is best obtained from local miners or brokers. On the right you see Pansy, a member or the Apache tribe, and Alice Drummond. We have been buying rough from Pansy for many years and never cease to admire the beauty of the material she and her family members extract from the earth.
Apache Gems was founded in 1987 representing San Carlos Apache Gemstones in the Gem & Jewelry Industries. Offering a wide variety of Jewelry and Jewels from the continents all to the highest standards of quality. Our company now features access to a worldwide network of businesses and trade services. We are based within the San Carlos Apache Reservation in Arizona operated completely by San Carlos Apache Members. Promoting First Nation businesses and Global Trade routes.
Here is a suite of faceted peridot gemstones cut from San Carlos material. These stones r
ange in size from 1.93 to 7.3 carats. Less tha n one percent of the peridot from this locality is suitable for faceting. It is extremely rare to
find a flawless San Carlos peridot that weigh s more than 1 carat; and equally rare to find a gem of reasonable clarity that weighs more
than 5 carats. The gemstones shown above r ange from VVS to SI2 in clarity. San Carlos pe ridot comes in a range of colors; from bright
yellowish green (The center stones above) to dark sligthly grayish greens (The large oval)
to material that is almost black (Not shown). Although the light yellowish green stones co
mmand the highest prices, the darker colors are also attractive and work well in men's rin
gs or jewelry designs where more subtle colo rs are desired.
Others; minor production
USA : New Mexico (Kilbourne Hole) Pakistan Mexico (Chihuahua)Norway Ethiopia Australia China South Africa
• North of Mogok Stone Tract• Bright green euhedral crystals in weathered serpentine (ultrabasic rock). • Renowned for color, considered the finest peridot in the world. • Have a "sleepy" appearance due to numerous small crystallite inclusions. • Once an important source, not presently.
MYANMAR (BURMA)
http://www.burmarubies.com/Peridots.html
Burmese folklore says that the gem slows the ageing process of the wearer !
The Pyaung Gaung area o f the northern Mogok vall
ey is now probably the wo rld's top source of this fas
cinating gem. There are t wo principal mining sites i
n Pyaung Gaung, with the newer area producing sto
- nes of a yellowish green s hade, and the older area s tones of a bottle green hu
e, with minimal hints of y ellow. While the new min
e color is similar to perido t produced in other regio
ns of the world, old mine Burma peridot, with its cl
arity, richness of color, an d remarkable size, is far s
uperior as a gem material . Many people have never
seen peridot of this qualit y and saturation level, an d are both surprised and i
nfatuated after their first encounter.
A 2 2 ct. Burmese Peridot
An example of Mogok peridot.
http://www.palagems.com
Similar to the Burmese and Egyptian localities, which also produce primary crystal formations, the Pakistani peridot forms in pockets, in high temperature veins so the material is virtually transparent. The Pakistani peridot shows inclusions which have not yet been positively identified as of this printing, however material has been submitted to the GIA for analysis. Prices for over 15-ct gems will perhaps command a premium comparable to the finest Burmese stones.
Pakistan Deposits
http://www.palagems.com/gem_spectrum1.1.htm
New inclusions in Pakistan Peridot:
- Vonsenite Ludwi gite needles
This new type of incl usion was analyzed i
n more details by m - eans of X ray analys
es (Gandolfi Camera)) ))))))))) ) ))))))
ope analyses in conj -unction with an EDS -system (semi quanti
tative chemical infor mation). In this way,
combining the two methods, the
inclusions could be determined definitely. This i - s a portion of a needle like black inclusion, whic -h was analyzed by the Gandolfi method. SEM im
age (SEM Laboratory, University of Basel), cryst al diameter is 0 .2 mm. It was separated from an approximately 60 carat rough Pakistani Peri
