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Ratanakiri Zircon
"White or colourless Zircons are used in lieu
of Diamonds by wealthy natives in Ceylon."
A. H. Church, Precious Stones (1905)
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Famous for
Angkor Wat (pictured), Cambodia is
also the world's premier source for
Blue
'Ratanakiri' Zircon |
Before I begin my take on this gem, I've got a bit of a
confession. Ratanakiri 'Blue' Zircon is one of
my favourite gemstones. Apart from being
one of December's birthstones (my birth month), Ratanakiri Zircon has a uniquely attractive blue
colour that you won't find exactly in any other
blue gemstone. Sure, other blue gems can come
close (or perhaps Blue Zircon comes close to
them), but either way, for me this gem has a
certain unexplainable, 'je ne sais quoi'.
Another gemstone writer, Yasukazu Suwa agrees
with this view, describing its colour as
possessing "a character that is not seen
elsewhere, even in Sapphire or Aquamarine". He
continues, adding: "If a fancy Blue Diamond
showed this colour, it might exceed $80,000 for
a 1 carat stone" (2001). For most of us, this is
well outside our gemstone budget, so thankfully
Blue Zircon is far more affordable.
Ratanakiri Zircon is a commercial name for Blue
Zircon from Cambodia or more specifically, Blue
Zircon from Ratanakiri, a Cambodian deposit
noted for yielding some of the world's finest
specimens. Cambodia is generally regarded as the
world's premiere source for this gemstone and
its other Zircon deposit is located at Preah
Vihear, about 100 kilometres north of the famous
Angkor Wat. But in my mind, Ratanakiri is 'the
place' for Blue Zircon. Out of the way and
exceptionally beautiful, 'Ratanakiri' means
'gemstone mountain' in Khmer. Ostensibly named
after the element 'zirconium' present in its
chemical composition, the gem name 'Zircon' has
two possible etymologies; one is the Arabic
'zarkun' (red), another is the Persian words
'zar' (gold) and 'gun' (colour). However, don't
be confused by the colours indicated by its word
origins. Zircon comes in an array of colours,
including blue, champagne, coffee, cognac,
golden, green, honey, orange, red, white (colourless)
and yellow. It also has an assortment of
historical and commercial names, which at times
can get pretty confusing. Jargon is pale yellow;
Jacinth is red; Hyacinth is yellowish-red (or
perhaps even blue); Matara Diamond or Ceylon
Diamond is white (more on this colour shortly);
Starlite or Siam Zircon is blue; and Ligure is
apparently generic.
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Ratanakiri
Zircon 9K White Gold Ring |
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A gemstone since antiquity, Zircon has been found
in some of the world's oldest archaeological
sites, which is no surprise given the mineral's
durability. As mentioned previously in 'A
Gemstone's Journey' (Chapter 1), a tiny mineral
fragment of Zircon discovered in Western
Australia is the earth's oldest known object.
Zircon is rich in history and legend, appearing
in several ancient texts, including the bible
and the Hindu poem of the mythical Kapla Tree,
which was bejewelled with leaves of Zircon. Some
sources mention a Jewish legend that names the
angel Zircon as the guardian appointed to watch
over Adam and Eve in the Garden of Eden (given
how this played out, it must have been a
thankless task). Called by its ancient names,
Ligure and Jacinth, Zircon gets several mentions
in the bible. Firstly, as one of the 'stones of
fire' (Ezekiel 28:13-16) that was given to Moses
and set in the breastplate of Aaron (Exodus
28:15-30) and secondly, as one of the 12
gemstones set in the foundations of the city
walls of Jerusalem (Revelations 21:19). Andreas,
the Bishop of Caesurae, who wrote in the late
10th century, was one of the earliest writers to
link the apostles with the 12 gems of Jerusalem.
He associated Jacinth (Zircon) with the
Apostle
Simon. According to its mythology, Zircon
represents purity and innocence. Like so many
other gems whose changes in their colours or lustre are said to be indicative of their
wearer's mood, health or fate, Zircon's loss of
lustre apparently means danger is looming.
As a jewellery gemstone, Zircon has enjoyed
several peaks in popularity. In 16th-century
Europe, Italian jewellers featured Zircon and
later it was also used in Victorian jewellery,
but it wasn't until the 'roaring twenties' that
Blue Zircon got its first taste of modern
popularity.
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Zircon & Diamond 9K Yellow Gold Ring |
Ratanakiri Zircon comes in unique blues, often
due to greenish tints, and is typically
eye-clean (no visible inclusions when the gem is
examined six inches from the naked eye),
although you can expect some inclusions under
magnification. As Ratanakiri Zircon's
transparency can decrease in the darker tones,
gems with medium to light colours are generally
preferred. This will maintain the gem's beauty
by affording visibility to its other optical
attributes. Zircon is strongly doubly
refractive, which means light splits into two
rays as it passes through the gem. This is
immediately visible, even to the untrained eye,
as a doubling of the facets, although this is
somewhat dependant on the angle of observation.
More pronounced in thicker gemstones, double
refractivity does not make the gem more
brilliant per se, but often results in beautiful
sparkling mosaic patterns and optical depth.
Other key attributes of Zircon are its beautiful
Diamond-like sparkle, brilliance, fire and
lustre. In order to maximise these
optical properties, Ratanakiri Zircon needs to
be carefully cut. Thankfully, well cut Blue
Zircons are usually available. While some
sources maintain that round cuts are most
commonly seen, in my experience, all the classic
shapes and cuts are available, including
emerald, heart, marquise, oval and pear, as well
as rounds. Although it is mined in Cambodia,
most Ratanakiri Zircon, as well as Zircon from
Nigeria and Tanzania, is cut in my adopted
hometown of Chanthaburi, Thailand. At present,
this town is the only primary source for
finished Zircon, with gems over 1 carat
increasing in rarity, availability and price.
Another source for Zircon is the alluvial
(sedimentary) deposits of Sri Lanka. During my
years of living in Chanthaburi, I have heard the
odd 'rumour' that Zircon is still mined in
Thailand, but I have yet to find any hard
evidence to support this.
Its Diamond-like characteristics, along with its
versatile colours continues to make Zircon one
of the most desirable gemstones for those clever
enough to appreciate the differences between
this genuine gem and a similar sounding
synthetic. While its other colours are
attractive, it's the exquisitely unique blues of
Ratanakiri Zircon that has captured my
imagination since I first saw it almost a decade
ago.
White Zircon
As
alluded to in this section's opening quote, Zircon
is the natural gemstone that possesses a sparkle
and looks most similar to Diamonds.
Historically, its use as a Diamond substitute
probably originates in Ceylon (Sri Lanka after
1972) in the late 18th century when white (colourless)
Zircon was mined at Matara, which is located on
the island's southern coast. It is from this
locale we get the historic commercial names
'Matara Diamond' or 'Ceylon Diamond'. Please
note that marketing Zircon solely using these
names today would be misleading as it is not
'Diamond' in composition. Zircon's high index of
refraction (click here for more) give this gem
its visual resemblance to Diamonds, resulting in
a sharp brilliance, playful scintillation
(sparkle), Diamond-like lustre (variously
described as adamantine or sub-adamantine,
click here for more) and high fire (also known as
dispersion, this is the splitting of light into
its component colours). With the advent of
manmade synthetics, such as cubic zirconia and
moissanite, Zircon is no longer the pre-eminent
Diamond substitute, but thankfully, this
fantastic gem is today valued for what it is,
rather than for just looking like something
else.
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One thing that gets me frustrated is
when poor old Zircon gets unfairly
confused with that cheap synthetic
Diamond imitation, cubic zirconia. While
their names sound similar and White
Zircon was once regarded as an excellent
Diamond alternative, this is where any
similarity ends. Zirconium oxide was
discovered in 1892, but it wasn't until
1937 that cubic zirconia was discovered
in its natural state. In nature, cubic
zirconia's crystals are way too small to
be cut as gemstones, so the two German
mineralogists who made the discovery
didn't even think the mineral important
enough to give it a formal name. In the
seventies, Soviet scientists at the
Lebedev Physical Institute in Moscow
perfected growing cubic zirconia
crystals in a laboratory. They named the
jewel 'fianit', but unfortunately for
our friend Zircon, the name didn't catch
on outside the USSR. The institute
published their results in 1973 and by
1976, cubic zirconia was being produced
commercially under the trade name 'djevalite'.
By the eighties, cubic zirconia was mass
marketed as the Diamond substitute of
choice. In my mind, gemstones are formed
within the earth, not a laboratory.
Remember, for a gem to be a gem it must
be beautiful, durable and rare. As they
can be made anytime, man-made gems are
not rare, so are these 'impostors from
the factory' even really gems? Zircon is
a real gemstone and cubic zirconia is
not, please don't confuse the two. |
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