THE SIX FACTORS THAT AFFECT QUALITY and VALUE
Size | Shape | Color | Luster | Surface Quality | NacreThickness
SIZE
Natural pearls are sold by weight. Until relatively recently,
they were weighed in “grains,” with four grains equal to one
carat. Today, however, they are usually sold by carat weight.
Cultured pearls are sold by millimeter size (one millimeter equals
approximately 1/25th inch): their measurement indicates the
diameter of round pearls, and the length and width if not round.
The larger the Pearl, the greater the cost. A 2 millimeter cultured
Pearl is considered very small, whereas Akoya cultured pearls
over 8 millimeters are considered very large; in South Sea pearls,
an 8 millimeter Pearl is small, 13-15 millimeters is average, and
over 16 millimeters is very large.
Large cultured pearls are rarer, and more expensive. In
Akoya pearls there is a dramatic jump in the cost after 7 1/2
millimeters. The price jumps upward rapidly with each half-
millimeter from 8 millimeters up. In South Sea and Tahitian pearls,
cost is also dramatically affected as sizes exceed 15 millimeters.
As we have mentioned, even though size is determined
primarily by the size of the nucleus implanted in the mollusc, the
larger the implant the greater the rejection and death rate. In
addition, the larger the nucleus, the more blemished, discolored,
and misshappen the pearls become, reducing the number of fine
pearls even further. This is why they are so much more expensive
than smaller pearls.
Size | Shape | Color | Luster | Surface Quality | Nacre Thickness
SHAPE
Shape in pearls is divided into three categories: spherical,
symmetrical, and baroque. The rarest and most valuable is the
spherical or round pearl; these are judged on their degree of
“sphericity” or roundness. While fine pearls that are perfectly
round are extremely rare, the closer a pearl comes to being
perfectly round, the more expensive it will be. Pearls with shapes
such as the teardrop or pear-shape are symmetrical pearls, and
are judged on proportioning, outline and good symmetry; that is,
whether they have a nice, pleasing, well-balanced shape.
Symmetrical pearls are usually less expensive than round pearls
--although there are some exceptions-- but much more expensive
than baroque pearls, which are irregularly shaped pearls.
Any strand of pearls should be well matched for shape, and
when worn give the appearance of uniformity.
New shapes are being produced today that don't really fall
into any of the three categories above. These include "coin"
pearls, which look like flat coins; thin, rectangular "bars";
"potato" pearls, which resemble an oval potato; and "ringed" or
"circle" pearls, which exhibit concentric rings from top to bottom.
Terms such as semi-round and semi-baroque are also used.
These are terms applied to pearls that are "out of round” but not so
much that the irregular shape is interesting, or distinctive. These
cost much less than other shapes.
Size | Shape | Color | Luster | Surface Quality | NacreThickness
COLOR
Color is an important factor to consider for several reasons.
Individuals have very personal preferences in terms of color based on
their own skin, eye, and hair color and should select a color that is
best suited to themselves. Color also affects costs because some
are rarer than others. Perhaps most important, there are more
colors of cultured pearls being produced today than ever before,
offering unusual and distinctive alternatives to traditional white
pearls, and additional pearl choices for any occasion.
How to Evaluate Color
For white cultured pearls, there are two principal elements
involved in evaluating color: body color and overtone. Some also
include "orient" in the evaluation of color, and when it is present, it
certainly affects the overall impression of the color seen. The
"body color" refers to the basic color, i.e., white, cream, yellow. The
"overtone" refers to the presence of a secondary color (its "tint") ,
usually a pinkish, greenish, silver or blue tint. When we speak of
color and pearls, we are referring to the combination of the body
color and overtone. White-rose would mean white pearls with a
rose-colored overtone (tint) ; naturally white pearls with a blush of
pink are rare and expensive. Creamier pearls are less rare and more
affordable. In white pearls, the rarest and costliest overtone is "pink"
(rose`); a green overtone is considered less desirable in white pearls,
and its presence reduces value.
In pearls that have a "fancy color" or hue-- a distinctive color
clearly distinct from the “white”/"off-white" category-- there is an
additional color element: tone. This refers to color intensity, and is
graded from "Light" to "Dark." A dark yellow pearl, for example, will
have a much richer color than a light yellow pearl; it is also much
rarer, more desirable, and costlier.
In naturally "black" cultured pearls, the color can range from
light gray to dark gray to black, and also includes blue and green;
over-tones are usually green or pink (rose`). In black pearls, a green
overtone is the rarest and most costly, especially when it results in
an intense "peacock" color. A pink overtone in gray or black pearls
creates mauve or "eggplant" colors. These are very lovely and
distinctive, and also sell at a premium.
Cultured pearls are available in many natural colors-- white,
gray, black, pink, green, blue, gold-- from many parts of the world.
The Philippines are known for natural yellow and golden pearls;
Tahiti, other islands of French Polynesia, and the Cook Islands for
naturally black cultured pearls.
Fancy-color pearls can be very rare and, depending upon the
color that interest you, difficult to find. Anyone searching for a fancy
to see the full range of colors available. This will help you select a
color with which you will always be pleased.
LUSTER
When you see a fine pearl, the first thing you notice is its
lustrous glow. Luster is not a superficial "shine" such as you see in
imitation pearls, but an intense brightness that results from rays of
light traveling through the numerous layers of nacre and being
reflected back from within the pearl. One might describe it as a
"shine with depth." In a pearl with good luster, there will be a sharp
contrast between the pearl's brightest area (the part in direct light)
and the shaded area; sometimes the contrast creates the illusion of
a "ball" within the pearl-- the more intense the image of the ball, the
better the luster. Luster is evaluated on the sharpness or brightness
of the reflection, which depends upon the quality and the quantity of
light reflected from its surface. This, in turn, depends upon the
quality and thickness of the nacre produced by the mollusc. The
thicker the nacre (and the smaller and more transparent the
microscopic crystals compromising it), the better the luster. When
numerous layers of nacre have crystallized properly, and each layer
is well aligned with the other, the results is an exquisite, intensely
lustrous pearl.
How to Judge Luster
Anyone buying pearls should take time to learn to evaluate
luster and, in particular, to recognize what is acceptable and what is
not acceptable; in particular, when luster is too low. Low luster not
only reduces the beauty of the pearl, but can provide a indicator of
very thin nacre. With Japanese pearls, low "chalky" luster usually
indicates a very thin nacre coating that can quickly crack, peel, or
simply wear off, leaving just shell beads. ( Imitation pearls will give
longer pleasure than poor quality, chalky cultured pearls, and usually
at a lower cost!)
Rule #1: Look for pearls with high luster. Luster is judged from
very high to very low. A pearl with very high luster will seem vibrant,
and the light reflection (the intensity of the "ball") will be sharp and
bright; a pearl was very low luster is dull, and the reflection hazy,
chalky or non-existent. To judge luster—
- Roll the pearls to view them from all sides to make sure the
luster is uniform.
- Examine under a light source such as a fluorescent lamp,
looking for reflections of the light off the surface, paying
particular attention to the brightness or sharpness of the
reflections. Avoid strong, direct light. If the available light is
too strong, hold your hand over the pearls to shade them, and
examine in the shadowed area.
Top quality Japanese Akoya cultured pearls can have a higher
luster than other round white cultured pearls because of the water
temperature in which they are produced. Cold water causes slower
nacre production, which normally results in superior crystallization
and over-all nacre quality. When the nacre quality is good, and it is
exceptionally thick, Japanese Akoya pearls can have incredible
lustrousness. But not all Akoya pearls are lustrious; luster can also
be very chalky, indicating very thin nacre, or poor quality nacre.
Size | Shape | Color | Luster | Surface Quality | Nacre Thickness
SURFACE QUALITY
Think of the pearl's surface as you would your own skin. Just
as our own is rarely completely free of little imperfections, so it is
with the pearl. Surface perfection refers to the pearls "skin" being
free of such things as small blisters, pimples, spots, or cracks.
Imperfections may also appear as dark spots, small indentations,
welts or blisters, or surface bumps. While occasional small
blemishes are not uncommon, if large or numerous they are
unsightly. A pearl with sizable or numerous blemishes may also be
less durable. The cleaner the skin, the rarer and costlier. If
drilled, the closer the blemish to the drill hole, the less it detracts
from both appearance and value.
Sometimes dark spots result from contact with perfumes, oils,
cosmetics, and so on. If superficial, they can sometimes be removed by
rubbing a mild polishing compound gently across the surface with a
chamois cloth.
How to Judge Surface Perfection
normally best for comparing quality factors in pearls, when
checking for blemishes, an intense light may highlight certain
types. When examining pearls for blemishes, it may be
helpful to check them with both diffused light and an intense
bright light.
- Examine against a dark background. A light background is
normally best for comparing most pearl characteristics, but
when checking for blemishes, it is sometimes easier to spot
them against a dark background.
- Examine while rolling. Place the pearl or pearl strand on a flat
surface and roll it to be sure you have examined all sides, and
so that the light catches any blemish and highlights it.
- Hold the pearls up and examine them while holding them out
in front of you, at eye level.
Practically speaking, there is no such thing as a "flawless"
pearl; they are exceptionally rare. In strands, this is even truer. You
must decide what is important to you in terms of color, shape, size,
and so on, and then balance the factors accordingly. I recommend
sacrificing the surface perfection somewhat rather than other
factors. Selecting pearls that are slightly blemished may enable you
to purchase pearls with thicker nacre, a more desirable color, or
larger size. Also keep in mind that if the pearl has intense luster,
most blemishes won't even be noticed; high luster helps conceal
them! A dull chalky white pearl, however, will show every blemish, no
matter how small.
Avoid pearls with cracks. Cracks can be serious and may lead
to peeling nacre, especially if they nacre is thin.
Size | Shape | Color | Luster | Surface Quality | NacreThickness
NACRE THICKNESS
Whether natural or cultured, thethickness of the pearl's nacre
and its quality is what gives the pearl its unique beauty. The thicker
the nacre and the better the nacre quality, the more lustrious and
iridescent-- the more exquisite-- the pearl.
Nacre thickness determines the pearl's longevity-- the thicker
the nacre, the longer the life of the pearl; the thinner the nacre, the
shorter its life. Finding the right balance to get an adequate nacre
thickness without jeopardizing other factors such as shape and
surface perfection takes skill and experience, as mentioned earlier.
The farmers producing the finest, most beautiful cultured pearls are
those who allow the nucleus to remain in the oyster the longest
possible time between implanting and harvesting, to obtain the
thickest possible nacre coating.
Nacre quality determines how the light travels through the
layers. Sometimes pearls with thick nacre fail to exhibit the intensity
of luster or orient that is expected. This normally results from the
particular way in which the layers of nacre crystallized. For reasons
we don't fully understand, the nacre crystals have not formed with a
good transparency, the layers are not uniform, or they are not
properly aligned. We do know that the rate at which nacre is
produced affects its quality. If nacre is produced too fast, it will be
less transparent. The result is a pearl with low luster; light enters the
pearl, but less is reflected back. This is not necessarily bad. One
must always weigh the importance of one factor against another. A
thick-nacre South Sea pearl with subdued luster will be more
affordable than one with higher luster; this could be good if the pearl
still has a lovely character and, costing less, might enable you to
acquire a larger size.
