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How to Tell Original Turquoise from Fake?
Of all the natural substitutes, there are a few
common culprits. To distinguish between these and natural turquoise, it
is always good to know a bit of gemology.
Gem Chrysocolla
Turquoise is
often imitated by "fakes" such as the mineral
chrysocolla. This is actually a part of the chalcedony
group of stones, in which the mineral chrysocolla is
finely disseminated, giving the chalcedony an intense
medium blue green color. However, the refractive index
(RI) of chalcedony is 1.53 to 1.54, much lower than that
of turquoise at 1.61 to 1.65. You can test the RI with a
refractometer to find out whether its chalcedony or
turquoise. Whether its chrysocolla masquerading as
turquoise or the other way around will depend on which
is of higher value at the moment, you more liable to see
turquoise dressed up as the more valuable chrysocolla.
Amazonite
This also resembles turquoise and is
light green to greenish blue in color with a distinctive mottling and
grid like pattern not seen in turquoise. It also has a refractive index
of 1.52 to 1.53, much lower than that of turquoise, and shows an uneven
or splintery fracture as opposed to the conchoidal or granular fracture
of turquoise.
Variscite
It often has a veined or mottled
appearance with a yellowish-brown matrix, a close enough resemblance to
have earned the misnomers of Nevada or Californian œturquoise. However,
its refractive reading of 1.56 to 1.59 is much lower than that of
turquoise and it will appear pinkish when viewed through a color filter,
whereas turquoise shows no color change through a filter. Variscites
color should be a deterrent in itself, as it resembles that of only
poor-quality turquoise.
Howlite
This is a naturally opaque white stone
with a dark, spiderweb matrix appearance, similar to that of turquoise
and therefore commonly dyed to imitate the more expensive stone. A quick
and easy test to separate the two is a color filter; viewed through a
filter, dyed howlite will appear pink or red. Howlite also has the lower
refractive index of 1.58 to 1.60 to that of turquoise. As a third test,
albeit a destructive one, a drop of hydrochloric acid on an obscure spot
on dyed howlite will attack the stone and leave a distinct dull spot.
Synthetic Turquoise:
Synthetic Turquoise is
virtually identical to natural turquoise but will show
artificial-looking matrix as well as a distinctive darker blue, spotty
appearance on a lighter background, visible fewer than 30 to 50x
magnification. This appearance is better known as the 'cream of wheat'
effect and is a dead give-away.
Glass imitations
These will show a vitreous
luster on small fractures as opposed to the waxy luster of the natural
stone. Glass and plastic imitations will show signs of tiny bubbles
under magnification. Touching plastic imitation turquoise with a hot
point will melt the surface and emit an acrid odor. Another practice,
one that can trace its origins back to 2000 B.C., is that of
reconstituted turquoise. Known as faience during the Egyptian period,
the material consisted of a quartz paste that was shaped, glazed, and
fired to resemble sky-blue turquoise. Today, reconstituted turquoise
consists of pulverized turquoise rock, mixed with resin and injected
into a mold to form a solid brick, which is then shaped. Pulverized
pyrite is sometimes added to better imitate natural turquoise.
So, What to Do?
Don't despair, though. The
best solution is to buy your turquoise from a reputable dealer who won't
hesitate to discuss treatments with you and supply you with a written
guarantee that your purchase is nothing else but natural turquoise.
Always purchase your turquoise jewelry from a reliable jeweler.
Source: http://www.lapidaryjournal.com/feature/may03
Chinese Turquoise
Chinese turquoise today is usually stabilized
meaning it is epoxied. A side effect of the process is that stabilized
stone is less likely to absorb lotions and body oils, which may change
the color of the stone over time. Today China has mines that produce a
great deal of turquoise. Northwest of Shanghai is the Ma'ashan turquoise
mine, and the Hubei Province produces turquoise in colors reminiscent of
the now closed mines in Nevada. This turquoise ranges in color from sky
blue to spring green as well. Today there are no known producing mines.
Turquoise from mines in China accounts for about 80% of the stone on the
U.S. market today, due to the scarcity of American turquoise. Only a
handful of turquoise mines in the American southwest are commercially
operating...
Read more...
Turquoise Imitations
How does one select good-quality natural turquoise
and not get caught by natural substitutes or the multitude of synthetics
and imitations that have infiltrated the industry over the years?
Turquoise is often dyed and stabilized with resins to produce a harder
stone, which retains its color and polish. Reconstituted turquoise is
made from small chips and "chalk" to which dyes and plastic resin is
added. Pure turquoise is a relatively soft stone ranging between 5 and 6
on the Mohs scale of hardness. Most turquoise specimens are
cryptocrystalline, meaning that the crystals can only be seen by...
Read more...
Turquoise Facts
Turquoise came in Europe through Turkey, but
its origin was Persia, where it has been mined for thousands of years.
The blue color of turquoise was thought to have powerful metaphysical
properties by many ancient cultures. In ancient Mexico, turquoise was
reserved for the gods and could not be worn by mere mortals. In Asia,
turquoise was considered as effective protection against the evil eye.
In Tibet even today, turquoise is by far the most popular of all
materials used for personal adornment, and still play an important part
in religious ceremonies...
Read more...
Turquoise Myths
Turquoise has been a treasured gemstone around the world for thousands
of years. It was used for beads by the Egyptians as early as 5500
BC. The deposits in Sinai were already worked out by 4,000 BC. In many
cultures, Turquoise is regarded as a harbinger of good fortune, success
and health. In ancient Persia it was once believed that the wearing of
turquoise talismans would protect the wearer from death. It was
also believed – not only among Persians but also among a number of other
cultures – that a change in the color of the turquoise was a sign of
danger or illness...
Read more...
The Lore and Beliefs
The lore, beliefs and myths of turquoise not
just date back to the ancient times, but some people still hold some of
these beliefs today. Good Luck Charm? Because, over the millennia of its
use, much of the world's supply of the stone has come from Persia, the
number of superstitions surrounding Turquoise that originate from Persia
and the surrounding area of the Middle East is great. To begin, Hebrew
tradition states that Isaac opened the first mines in Persia. Having
seen the reflection of the new moon in a stone of Turquoise, a person
was believed to encounter good luck soon, according to Persian lore.
Arabian superstition said it was a lucky stone and that it had good
powers of benevolence. They also attributed the accumulation of wealth
and prosperity with the stone...
Read more...
Back to 'All About Turquoise' Summary
Turquoise, the robin's egg blue gemstone worn by Pharaohs and Aztec
Kings, is probably one of the oldest gemstones known. Yet, only its
prized blue color, a color so distinctive that its name is used to
describe any color that resembles it, results in its being used as a
gemstone. The true value of turquoise is in the beauty of the
stone. Buy at the level you can afford and buy what speaks to you, what
you find most attractive. There's no stone like turquoise, and rarely
are two pieces alike...
Read more...
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Different Fake Turquoise Types
