Featured Jewellery - Colored Gemstone and Pearl Jewelry

Colored gemstones

Colored gemstones and pearls are often lumped into a single category in the
jewelry trade, although there are countless varieties of both—hundreds of
different gems that all come in many different colors and originate from different
regions, affecting their hue, size, and quality.
Assessing the Quality of Colored Gemstones
Although they’re not commonly associated with stones other than diamonds,
the 4Cs can come in handy when shopping for colored gemstones too. That
said, the grading scales for colored gems are much less formal. Color, while
one of the most important determinations of a gemstone’s quality, is often
evaluated subjectively in terms of the hue of the stone. The color of a ruby,
like the one shown in Figure 4.6, might be judged to be “very red,” for
instance. So much for the scientific, letter-based grades assigned to diamonds!
Such a grading scale does not exist for colored gemstones quite simply
because there are so many different kinds of gemstones that it would be
impossible to build a color grading scale that worked for all of them. Unlike
with diamonds, professionals pay close attention to the quality of the tone
and saturation of the color for a colored gemstone. The richer and more
spectacular the color, the more the stone is worth.
Similarly, clarity and carat weight are very important for colored gemstones,
although the value associated with these characteristics might be harder to
understand. Good cut is also very important, although color and clarity
tend to take preference in grading quality. Colored gemstones still need to
refract light, but don’t need to do so as intensely as diamonds do in order to
be beautiful. On the other hand, there do exist on the market poorly cut colored
gemstones, which feature bad angles on the pavilion, or bottom, of the
gem that prevent light from reflecting well and cause the gemstone to look
dull. Cutters might purposely cut these gemstones that way to add weight
to the stones, so they can earn a higher price for a bigger carat weight. These
stones are called “windowed” because you can often see right through the
top to the bottom of the stone.
Assessing the Quality of Cultured Pearls
Most of the pearls you’ll find on today’s market are cultured pearls, so called
because most modern, commercial pearl development in oysters is initiated
by humans and therefore can’t be called “natural.” Very rarely, you might
run across real, natural pearls, especially in antique jewelry, but also occasionally
sold as loose pearls or in modern jewelry. What’s the difference? In
nature, a pearl is formed when an intrusive particle such as a piece of shell
becomes lodged inside a mollusk (often mistakenly called a pearl “oyster”).
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Figure 4.6
A colored gemstone is graded
based on the same 4Cs as a
diamond, except that each C
has its own considerations
unique to a colored gem.
To protect itself, a mollusk begins coating the particle with nacre, a white,
lustrous substance. Over time, the mollusk secretes enough of this substance
to form a pearl. Unfortunately, these pearl mollusks have been overfished
over many years, so it’s rare to find real, natural pearls. The pearl trade
instead cultures the growth of pearls by implanting beads in the mollusks
and encouraging the growth of nacre.
As long as you look for good-quality cultured pearls, the fact that they are
cultured should have no effect. That said, some purist collectors like natural
pearls because they are made only of pearl nacre, whereas a cultured pearl is
typically a few millimeters of nacre coating a shell bead (depending on the
quality and variety of the cultured pearl, this coat of nacre can be very thin
or very thick, but some people prefer the rare all-pearl option).
Shopping for cultured pearls is very different than shopping for colored
gemstones, even though they’re often grouped in the same category. Dealers
do use a grading system (though not a universally recognized one, so grades
can vary depending on the source), by which AAA is the best quality and C
is low quality. The grades represent a combination of different quality factors
in cultured pearls, which include the following:
■ Luster. A pearl with great luster will have a sort of luminescence
about it, an inner glow with a colorful sheen. Pearls with poor luster
will appear flat, white, and even chalky. Good luster is the sign that
the pearl is covered with a thick coat of nacre. Without sturdy nacre,
your pearls could start to peel, leaving you with an ugly shell bead
underneath.
■ Surface. Almost all cultured pearls will have at least some very slight
blemishes on them; those blemishes are how you can tell they’re real
pearls (as opposed to glass simulants), because they’ve spent time in
the water and have been exposed to the wear of water and sand. That
said, the less discernable the blemish, the more valuable the pearl.
Very good quality pearls will have barely noticeable blemishes, while
poorer quality pearls will show quite a few spots or cracks.
■ Shape. The rounder the pearls, the more valuable they are. However,
there are beautiful varieties of pearl shapes, including tear-shaped or
drop-shaped, potato-shaped, and “baroque,” or asymmetrical shapes,
which are gorgeous and unique.
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The Ins and Outs of Jewelry Buying Chapter 4
■ Color. Depending on the variety, pearls can come in many different
colors. Some colors are natural, and some are not. You should do a
little research on the variety of pearl you plan to buy to find out what
colors are possible.
■ Size. Different from diamonds and colored gemstones, pearls are measured
in size, not weight. Size is determined typically by the diameter
of the roundest part of the pearl, measured in millimeters. Again, size
ranges depend on the variety of pearl being measured. Some can start
at 1 or 2 millimeters and only get as large as 5 or 6 millimeters, while
others can grow as large as 20 millimeters. Bigger pearls are often
more valuable, depending on other quality factors, of course.
There are several varieties of cultured pearls, each with its own unique set of
characteristics. Akoya cultured pearls are the type most people think of when
envisioning pearls. They’re the small, white, round pearls you often see as
strands. Traditionally they come from Japan, though they are also available
from China. South Sea cultured pearls are the pearls you see movie stars and
politicians wearing—huge, white or golden cultured pearls from Australia,
Indonesia, and the Philippines. Black pearls (often known as Tahitian pearls
because many of them originate in French Polynesia, of which the island of
Tahiti is part) are also sizeable, but come in wild colors such as greenish gray
and pinkish black. And freshwater pearls come in all shapes, sizes, and colors.
Often farmed in the lakes and rivers of China (though some are produced
in the United States and other countries), these pearls run the gamut
between “rice krispie” shapes and large, round, beautiful forms, in a variety
of gorgeous colors. While akoya, South Sea, and Tahitian are often pricey,
freshwater pearls are often more affordable.