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Opal
Valuation and Terminology
Opal comes in many forms and from
many places. It can be white very little color (what most people know), clear
crystal and a flash of color (mall jewelry), orange Mexican fire opal or the
rare black opal. It can be a dull blue opal, a green-blue opal or a fiery multicolor
stone that dances like no other gemstone. It can be from Hungry, Peru, Mexico,
Nevada, Australia, Brazil, Honduras, or even now "chocolate" from
Ethiopia. All of these varieties can run from dull (no color) to some specs
of color, to flakes, to flashes and to just solid single colors. It can appear
to be a simple rock or the brightest, liveliest stone you have ever seen. All
of these diverse factors make this discussion very complex and confusing for
most people.
In addition to solid, natural
opals (which will be my focus), opals are solid as doublets (or doublets), triplets,
mosaics, lab created and even simulated. This makes it even more difficult for
the consumer. I will attempt to make it simple and understandable. I will attempt
to present the meaningful discussion of the factors which govern the pricing
and evaluation methods that are used by the opal industry and dealers when selling
loose opals or finished jewelry. My focus will be on valuation of solid natural
Australian opals with visibly displayed color, called precious opal. My opinion
of opal is it must have an appearance that is visibly appreciative, that is
unique, eye catching and will look good in a jewelry mounting. If you want plain
dull white opal buy pearls at least they shine. If you want black opal with
no color then buy onyx at least it shines as well. A complete guide to opal
identification and valuation would take 200+ pages and many hundreds of photos.
We will present a concise but complete description of the process so a layman
and a jeweler can have the information they need to make an informative buying
decision. Opal identification and valuation is not standard there are no industry
guidelines like for diamonds and many colored stones. Even most laboratory and
Gemologists cannot correctly identify or evaluate an opal, it is left up to
"field" experts, the market and opal dealers to set the trend and
educate the public on the complex nature and methodology of opal valuation.
Evaluating and pricing an opal is more difficult than any other colored stones
especially diamond. So lets get started and if you do not understand or you
need more detailed information please e-mail us or call us toll free in the
USA (800) 376-6725. Below are the sections we will focus on.
Valuing
Opals/Types
Opals are unique and no two are
exactly alike. All types come in various shapes, colors and qualities. Important
factors in choosing and valuing an opal are.
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Size/Shape
Opals like diamonds are measured
by carat weight. Quality opal can command a price per carat similar to that
of diamonds.
Generally opal size and shape
pertains to the opals value for jewelry use. A calibrated oval gemmy stone 1
to 3cts will have the most value for rings and earrings while a 3 to 5cts+ may
be more valued for pendants. Opals that are not a standard shape such as oval,
pear, heart, round, or marquise are called "freeform". These have
less value when appraised but to the right customer and jewelry designer a freeform
opal offers unique possibilities for custom designed jewelry. Opals can also
be custom cut (by our company) from rough opal into any shape to fit the designs.
Larger opals even of high quality is great for big pendants and collectors as
keepsakes but are usually difficult to sell. On a per carat basis a 5ct black
opal with red multicolor has more value than a 25ct stone too big to set into
jewelry. The shape a size can also affect the cut quality valuation. A stone
should have a good thickness for setting and wearability. The dome height of
an opal also helps display or disperses colors better than a low dome stone.
The quality of the polish will also determine how much reflection you get. The
next subject, color/directionality determine a major factor of cost.
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Color/Patterns
The beauty of an opal is in its
color and generally speaking, the more colors in an opal, the more valuable
the stone. How the colors are displayed and move represents the patterns.
Opal colors literally transverse
the rainbow but the major color combinations are blues/greens and multicolors.
The more reds with any of these color combinations the higher the value, and
in multicolors opals the more variation of opal the more value. Some opals also
have only one color such as green, blue. Orange, or yellow. Of course opal colors
to the buyer is what is most important- some people only like blue/green opals,
while others love the wide variety of a red multicolor opal. Now there is a
blue/green Peruvian opal that has no fire.
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Clarity/Brilliance/Brightness
A clear opal with rich vibrant
colors will be highly valued. An opal with inclusions or opaque patches will
not be as valuable as a clear stone. White opal is sometimes called "milky
opal" due to its translucent to opaque whiteness, which can have all traditional
colors against this white background.
Mexican fire opal in reality is
just orange, yellow, red, or a combination of body color and does not have "fire"
or flashes like most opal. There is a type of Mexican opal with intense red,
orange, green, yellow, and sometimes blue flashes that come from inside the
stone. This is highly prized and can fetch thousands of dollars per carat. The
problem with most Mexican opal is the "stability"- many times the
opal crazes or cracks 6 months after you buy it. That is why Opals International
keeps all its opal uncut for up to a year before selling and then offers a one
year industry exclusive guarantee against natural crazing and cracking so the
type of colors, variation of color and intensity of color plays a major factor
in opal valuation.
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Valuing/Types
The base or body color determine
the first factor-type- most common white opal or light opal which can display
all the colors of the rainbow on a pale background. The terms red orange and
green "fire" describe the dominant color of the stone. White opal
generally comes from Coober Pedy and Mintable in South Australia. Opal of this
nature can be 0.50$ per carat and up to $500 per carat for top gem full fire.
Crystal/semi-crystal opal merely
means that when held up to light you may see through the stone. But a good crystal
opal from South Australia Coober Pedy or even Lightning Ridge (home of the black
opal) should display a blue-green color pattern or multicolor display Most of
the very bright gem grade opals on our website are crystal opals. Some of the
finest opals ever found were Top Gem crystal opals displaying vibrant red multicolor
flashes that dance with the stone, along with every other color imaginable crystal
opal is transparent with a sharp difference in diffracted color from inside
the surface of the opal. Most of the inlay jewelry on our site and Kabana use
very bright blue/green crystal with epoxy enhanced background. Crystal opals
with good color are priced from $200/carat to $3000/carat for top gem multicolor
opals.
Boulder opals are usually a brown
base with "thin" color veins splashed across or through the opal and
ironstone matrix. Most of these opals come from Queensland, Australia. Boulder
opals typically are blue-green in color but can also have in rare cases multicolored
patterns the same as crystal opals. The trick is to cut the color section in
a way that can maximize the opals appearance. Boulder opals are typically "freeform"
shapes in nature and can be quite large. Boulder opal is a solid opal, which
consists of a fine layer of opal that has been deposited naturally on and in
the fissures of ironstone rock. The gem opal is usually filling crevices and
cracks within the ironstone matrix. Boulder opal can be extremely bright and
interesting. A favorite of gem and jewelry designers often being a part of Award
Winning Artistic Designs. Very bright, large multicolored boulder opals are
extremely rare. Most common boulder opals of any value are a blush-green in
nature and freeform shapes.
Black opal comes primarily from
Lightning Ridge, New South Wales Australia. Some black opal is also found in
Nevada as a form of fossilized tree limb, but stubble gem grade material from
Nevada is rare. Technically black opal has a dark body color and can range from
jet black to a gray-black background. Because of the darker base the colors
reflect stronger and are highly sought after due to the rarity and beauty of
the black opal. The brighter, more unusual and sharper/vivid the colors the
more valuable. In the same mining area, a form of Top Gem Crystal with a darker
background can be found which is considered the best crystal opal hands down,
called "Black Crystal". It is very dark, very bright, all colors,
vivid, and if you hold it up to light you can see through it, but placed in
jewelry you see nothing but color. Most black opal is a blush-green color but
can be any combination including gold, violet, yellow, and orange. Probably
the rarest of all gems including fancy color diamonds is a very black, dark
background with reds/pinks and other colors splashed across the stone with intense
brightness and a "dance" that no stone can match. The top stones of
this description can fetch $40,000 or more per carat. A Harlequin pattern black
opal is so rare that it can be compared to a red diamond. Valuation of black
opal with just blue will run from $100 to $500/carat. As you add green the price
goes up. The darker the stone the more money, the brighter and more reds the
more money. Nice stones less than 5cts run from $2000/ct to $5000/ct. The patterns
can increase values dramatically.
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Directionality
This refers to how the opal exhibits
colors/patterns and brightness from various angles. A perfect opal is not directional
meaning you can see colors/patterns at all angles as you look at it. This is
most prized but not most common. It seems even in bright stones that at some
angles the stone looses its life that is why some stones are perfect for pendants
and earrings in one orientation, and should be tested for viewing quality in
all of these orientations before buying. Other stones are perfect for rings,
as the stones look great in all angles. A stone that only looks good at one
angle should have much less value than a similar stone that is great at all
angles. And of course there are varying degrees of "directionality".
Along with this discussion the lighting situation should be considered. In jewelry
stores bright halogens can make almost anything look good but in the case of
opals, softer lights, darker light can often have a dramatic effect on how your
opal looks. All opals should be viewed in florescent light as well as natural
light to see how it looks. An opal stone that looks good in all lighting will
be the most valuable, while a stone that needs lots of direct light to display
colors will not be as prized. Next we will discuss opal brightness and how it
is measured, probably the single most important factor in determining value.
The
Pricing Guide to Opals
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