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Zircon
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Zircon is a natural stone often used to imitate diamonds. It is often
confused with cubic zirconia which is a synthetic stone.
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General Information Where
mined Search
Birthstones
Anniversary Lore
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Main Birthstone Page |
| Colour |
Colourless, yellow, brown,
reddish-brown, orange, light blue, light green, light purple, pink |
| Hardness |
7.5 |
| Specific
Gravity |
4.6 - 4.8 |
| Refractive
Index |
1.930 - 1.987 |
| Double
Refraction |
.059 |
| Lustre |
Adamantine |
General Information
Zircon is a famous gem of many colours, known for hundreds of years for
its lustre
and fire.
It is often looked upon as a cheap diamond
stimulant, but is, in fact, a valuable gem. Its colour diversity is
caused by traces of certain elements, some of which are radioactive.
Zircons containing radioactive elements undergo a process called metamiction,
in which their inner crystal
structure becomes destroyed. These radioactive forms of zircon must
be heated to stabilize them for use as gems. In fact, almost all gem
forms of zircon (even those that are not radioactive) are heat-treated
to enhance their colour. Heating semi-transparent, greyish-brown or
reddish-brown zircons from most localities in an oxygen-free environment
gives them a blue colour. If these blue stones are then re-heated in
air, their colour turns golden-brown. Heat-treatment of certain zircons
also produces colourless gems.
The brilliant lustre
and fire
of zircon, combined with its hardness
and range of colours makes it a most desirable gem.
However, it does have some undesirable traits. An
interesting and strange habit exhibited in only few zircons is that
their colour darkens and their lustre dulls upon prolonged exposure to
sunlight. This effect can be reversed by giving the stones a second heat-treatment.
It is also prone to cracking and chipping if banged too hard. For this
reason, care must be taken when cutting zircon. Zircon must also be cut
in a manner in which its strong double
refraction is least noticeable, to prevent it from appearing blurry
Brown Zircon is usually heat treated to change them to colourless or
blue Zircon. Blue stones that revert to brown will regain the blue if
reheated. Blue Zircon reheated in the presence of oxygen will change to
a golden yellow.
Zircon will have more wear on its facets than diamond. Zircon is
imitated by colourless glass and synthetic spinel.
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Where Zircon is mined
There are many places this mineral is found. Some noteworthy European
localities are Alta Fjord, Seiland Island, Norway; the Tyrol, Austria;
the Eiffel Mountains of Germany; and the Ural Mountains of Russia.
The worlds most industrially important deposits are in the heavy sands
of Queensland, Australia. Most gem grade Zircon comes from several
eastern Asian countries, where it is found in placer deposits as rounded
water worn stones, often associated with other gem materials. These
countries are Sri Lanka (Mynamar), Burma (Ceylon), Vietnam, Cambodia,
and Thailand. In Madagascar, several localities have yielded large
crystals, and some very large crystals have come from Jaguaracu and
Pocos de Caldas,
Minas Gerais, Brazil.
Canada contains many excellent localities for this mineral. Enormous
crystals, up to a foot long in a few cases, have been found in Renfrew
Co., Ontario. Large crystals also come from Bancroft and Dunngannon,
Hastings Co., Ontario, and transparent pink crystals were found in the
McLaren Mine, near
Perth, Ontario. Large, well formed crystals are famous from Tory Hill,
Wilberforce, Haliburton Co.,
Ontario. Zircon associated with Aegirine occurs in Mont Saint Hilaire,
Quebec.
In the U.S., Zircon is found as small, occasionally transparent pebbles
on the beach sands of North Carolina, South Carolina, Georgia, and
Florida. Perfect, loose crystals are found in the gravel in Henderson
Co., North Carolina, and shiny black crystals were discovered in the
Eureka Tunnel, St. Peters Dome, El Paso Co., Colorado. Other famous U.S.
localities are Sparta, Franklin, and Ogdensburg, Sussex Co., New Jersey;
and Bedford, Westchester Co., New York.
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General Information Where
found Search
Birthstones
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Main Birthstone Page |
Birthstone Months with Zircon
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Anniversary Gemstone for Zircon
Zircon is not an anniversary
gemstone.
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Zircon Mystical Properties
Zircon supposedly helps one be more at peace with oneself.
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More Zircon Lore
Zircon was believed to provide the wearer with wisdom, honour and
riches.
The lost of lustre on a Zircon stone is said to warn of danger.
The name Zircon is from Zargun which means "gold
colour".
|
General Information Where
found Search
Birthstones
Anniversary Lore
All Gemstone Information
Main Birthstone Page |
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