For example, there are many amethysts available, even in the comparatively rare, deep rose purple color, but a client wishing to own a 5 carats bright and deep yellow-green demantoid garnet from Russia, or a fiery, bluish green Paraiba tourmaline from Brazil may have to wait until the jeweler can find them.
Colored gemstones and jewelry are sold by brick and mortar and internet jewelry stores, pawn shops, auctions and on home shopping networks. But there are only a handful of jewelers/gemologists who are experts in the field of colored stones. As always, know your jeweler and know his/her expertise. Find an expert, and you will buy something special that will be enjoyed by future generations in your family.
THE COST AND QUALITY OF COLORED GEMSTONES:
Colored gemstones are more complex than diamonds. This is because nature produces so many species and varieties, and each variety grows in so many different shades and intensities of color. As an example, the purple amethyst quartz, the birthstone for February, grows in tones from very light violet to intense rose violet and costs from $2.00/carat to $800/carat. All colored gemstones have broad price ranges like that of amethyst, and these are based on carat weight, quality, history, demand, durability, comparative rarity, fashion and in rare cases geographic origin.
Like diamond, the heavier the colored gemstone the more expensive, all other factors being equal. Like diamond, there are 100 points to a full carat. Some colored stones are not weighed. Rather they are sold based on their physical dimensions. Examples would be the opaque colored gemstones like malachite, sugilite, lapis, coral, shell, chalcedony, cinnabar and of course the two jades, nephrite and jadeite, among many others.
Based on the comparative rarity of colored gemstone rough crystals, there may be large price jumps at certain carat weights for some colored stones. Sometimes the per carat price jumps at 3 carats; sometimes 5 carats; sometimes 10 carats. While demand is a factor here, the rarity of the rough crystal is the primary determinant of increased cost.
CARAT WEIGHT VS. SIZE:
A 2 carat diamond does not occupy the same space as a 2 carats sapphire which does not occupy the same space as a 2 carats rhodolite garnet, and on and on. The atoms of each colored gemstone combine in different patterns, and this creates a distinct density or specific gravity for each species. A 2 carat sapphire might measure 7.6mmm diameter white a 2 carats diamond might measure 8.1mm. While most colored gemstones are priced by the carat, the appearance of the stone in a ring for example is based on its size, meaning its surface dimension. The great designers of colored gemstone jewelry look at surface dimension and appearance rather than carat weight.
The quality of a colored gemstone is based on Color, Clarity, Shape, Cut and Laboratory Enhancements to Color and or Clarity. Of these factors, COLOR is the primary ingredient of cost and beauty. (Note the comparison with diamond where it is the cut, meaning the quantity and quality of brilliance and fire that is the primary ingredient of cost and beauty).
Hue: the actual color of the stone.
Tone: lightness to darkness.
Saturation: brightness to dullness.
Distribution: how evenly or unevenly the color is distributed across the top of the stone.
Because there are no universally accepted grading systems for hue, tone and intensity of color, experts will use descriptive words when trying to describe the color of both the most common and the rarest colored stones. For example, sapphire, a variety of the mineral species called corundum, grows in every color of the rainbow except red. In the variety of blue sapphire, the most common stones are either too pale or too dark. The rarer sapphires exhibit a vivid, bright blue with no black, gray or green. Nature produces greater quantities of the paler and darker sapphires. So when we discover the vivid, bright blue stones, the cost rises sharply because of their comparative rarity. These principles of common versus rarer color are true for all colored stones.
Cost is important but not the only factor to consider when selecting a stone. When we present blue sapphires, for example, we show stones in a wide range of blues, and then focus on the specific shade that most pleases the customer. This means presenting everything from the rarer blues to the more affordable navy or deep sky blue sapphires.
COLORED GEMSTONE ENHANCEMENT
To intensify, deepen and/or make the color more uniform
To remove a modifying color, leaving the rarer hue more visible
To mask or eliminate unsightly inclusions
To stabilize the structure of the gemstone
FEDERAL LAW REQUIRES ALL TREATMENTS TO COLORED GEMSTONES BE DISCLOSED SO CONSUMERS MAY MAKE AN INFORMED DECISION ABOUT THE VALUE OF THEIR GEMSTONE BEFORE THEY PURCHASE.
American federal law does not apply to the purchase of colored gemstones outside the United States. All enhancements affect the cost of colored stones, some by a little, others by a lot. Because most colored gemstones are enhanced, those that are not command premium prices.
There are many types and degrees of enhancements. Some alter color just a bit, while others are so extensive they create almost the full color of the polished gem. Some mask only a few unsightly inclusions, while others “burn out” an entire field of internal markings, leaving the stone nearly flawless — something that is fairly rare in nature. Many enhancements can be detected by experienced gemologists with standard laboratory tools. Other enhancements require advanced laboratory identification. Some enhancements are permanent; others are temporary, allowing a strong color to fade under certain circumstances. Your jeweler can provide an independent laboratory document identifying the presence of enhancement, the type of treatment used and the strength of the enhancement. This is especially important for the purchase of a ruby, emerald and sapphire. Customers should understand how the enhancement affects a stone’s quality, current cost and potential future value, especially if the treatment may not be permanent.
CLARITY, SHAPE, CUT & DURABILITY
Most colored gemstones grow in nature with heavy concentrations of flaws. We call these flaws “inclusions.” Some colored stones grow with relatively few inclusions. When inclusions are too heavy, light is diverted from its path and the stone appears flat or milky. When a stone is available with few inclusions, when most specimens of that variety grow with heavier flaws, its cost may increase rapidly because of the rarity of that crystal. As with diamond, inclusions that break open onto a surface might create a durability problem. Inclusions that block light and/or are visible to the eye may greatly reduce the cost of even some fine colors.
Colored gemstones grow in many shapes, influencing the shape of the polished gem. Most emeralds in the market are oval, square or rectangular, therefore a round emerald, especially a fine quality stone, may be pricier simply because there are comparatively few round emeralds available in larger carat weights.
As with a diamond, the quantity and quality of light that explodes from the surface of a colored gemstone has tremendous influence on the appearance of its color, and its ultimate cost. A rare color like a crimson red ruby that is poorly cut may appear flat and lifeless to the eye, reducing its value.
As a group, colored gemstones scratch and chip more easily than diamonds. Hardness refers only to the ability of a stone to resist being scratched while durability refers to the ability of a stone to resist chipping and abrasions. The hardest colored gemstones, sapphire and ruby, are still much softer than diamond, 20 to 40 times softer. If worn in rings daily, especially in larger sizes, they will scratch and chip over time. Discuss the hardness and durability of your colored stone with your jeweler, and receive advice on how to set it, when and where to wear it and how to keep it clean.
GEMSTONE DEMAND, HISTORY & FASHION
Regarding fashion, the clothing industry leads the way, dressing the modern woman each season, and colored gemstone designers follow suit. When the fall colors are in vogue, citrine, topaz, Malaya and spessartite garnets appear. When the richer winter colors of the holiday season take over, the deep purples and reds of amethyst, rhodolite garnet and red tourmaline fill the shelves of many jewelry stores.
Everyone knows that clothing fashion means temporary style. Gemstones and jewelry outlast trends, so clients should be thoughtful about their purchases of jewelry to accessorize certain outfits. Make certain that the stones and pieces you buy serve as timeless classics, as well as enhance the beauty of the current season’s wardrobe.
GEOGRAPHIC ORIGIN OF COLORED GEMSTONES
The geographic origin of most gemstones has no effect on cost or value. If the origin is accurately known, it can be an interesting part of the “story” created in the sales presentation. The origin of many colored gemstones can be determined by a combination of color and an analysis of the inclusions, which may be particular to the geology of certain areas of the world.
There are some exceptions to this general rule and even here, only certain qualities of stones from the list below will command a premium price. Most of these locations produce a wide range of quality and most would be considered typical commercial (mediocre) quality.
- Ruby, sapphire, jadeite from the Mogok River valley in Myanmar
- Electrically bright turquoise green tourmaline from the Paraiba Mine in Brazil
- Velvety soft, slightly violet blue sapphire from Kashmir
- Deep and fiery yellow green demantoid garnet from Russia
- Alexandrite chrysoberyl from Russia
- Siberian amethyst from Russia
- Oriental natural pearls from the Persian Gulf
Customers interested in these gemstones MUST have an independent laboratory report verifying geographic origin. Today, such reports may come from the Gemological Institute of America in Carlsbad, California, the American Gem Laboratory in New York or the Gubelin Laboratory in Switzerland.
THE COMPARATIVE RARITY OF GEMSTONES
Merchants of many luxury products overuse the word “rare,” to create an impression about the availability of an item. They use the term to increase the value of the item in the mind of the buyer. A good working definition of a rare gemstone is one that is very difficult for an expert in that stone to find, given a reasonable amount of time.
Most gemstones are not rare. In fact, most gemstones are commonly available, even if a jeweler is not aware of how to find them. Colored gemstones are comparatively rare when it may be more difficult to find one over another at any given time. Some rarer gemstones do not always cost more. It depends on consumer demand and the size and beauty of a particular stone.
Here are several examples to demonstrate the comparative rarity of colored gemstones:
Large quantities of amethysts in almost all depths and intensities of violet color are available. Certain colors of deep and bright rose violet amethyst are comparatively rare. A Siberian amethyst of 5 carats or more and of a particular intensity of rose violet color would be considered rare.
Rubies in most carat weights and intensities of pinkish-red, purplish-red, brownish red and orangey-red color are commonly available. Pure crimson red rubies above 5 carats are comparatively rare. An example of a rare ruby would be pure crimson red with minimal inclusions, without enhancements, 5 carats and over, from the Moguk River Valley in Myanmar.
There are large quantities available of most carat weights and most hues, tones and intensities of blue sapphire. Pure blue sapphires from Myanmar 5 carats and up, without enhancements and minimally included are rare. Certain slightly violet blue sapphires from Kashmir, with needle-like inclusions, creating a soft velvety texture from 5 carats and up are also rare.
Large quantities and most carat weights of all depths and intensities of emerald are available. Deep bluish green emeralds from Russia with minimal inclusions and no enhancements, from 3 carats and up are rare. Medium to deep bluish green and medium to deep yellowish green emeralds from the Chivor and Muzo mines in Colombia with few inclusions and not enhanced, 3 carats and up are exceptionally rare and almost impossible to find.
Substantial quantities and most carat weights of white opal from various parts of the world, those with milky colors and gemstones with intense play of color are available. White opals with exceptionally intense blue, green and orange play of color from Czechoslovakia are rare. “Crystal” opal from Australia with the 5 major colors is becoming more difficult to find each year. There are many black opals from Lightning Ridge Australia, and many with fabulous colors. However, a black opal with all 5 colors, with emphasis on red, orange and yellow, where the colors are arranged by nature in certain shapes and patterns that move as the opal moves is rare. Extremely fine opal from Ethiopia, the newest addition to the field of opal gemology, is currently common.
Substantial quantities, most carat weights and most colors of tourmaline are available. Exceptions include deep red tourmaline over 5 carats, with minimal flaws and enhancement by heat only; or deep and intense turquoise green electrically bright tourmaline from the Paraiba Mine in Brazil would be considered rare.
Imperial jadeite, the rarest green jade from Myanmar, is one of the rarest gems on the planet. Its color compares with the finest emerald. It is semi-transparent, with absolutely no veining or inclusions or enhancements of any type. It radiates a pure liquidy deep green. Intense and medium to deep violet jadeite, not enhanced, is comparatively rare, and becoming more difficult to find each year. Certain hues and transparencies of white and mustard color jadeite are also becoming more difficult to find each year. Most colors of nephrite, the second of the two minerals in the jade group, remain commonly available.
Demantoid Andradite Garnet:
This intense and exceptionally fiery yellow green garnet from Russia has always been difficult to find in larger carat weights. It is like a brilliant sun bursting out of a deep green sea when a stone is found with optimum color and dispersion. Definitely rare.
Alexandrite, the variety of chrysoberyl, which changes color under certain lights, is reasonably common in smaller sizes, from Brazil, Sri Lanka and India. However, true Russian alexandrite showing optimum color change, exhibits the pure reds and greens of one of the great gems of history and is almost impossible to find, even in Russian and European estate jewelry from the 19th century, which is one of its few sources today.
The garnet family of gemstones is interesting because there are a number of species that exhibit overlapping colors of orange, pink, brown, red and purple. The rhodolite garnet remains very popular and commonly available in small to moderate sizes in most of its tones and intensities of purplish and pinkish red. However, in larger sizes, even at 5 carats (but definitely at 10 carats) and with the optimum purplish red hue, this gemstone has become much more difficult to find; almost rare.
Summary Definition of Rarity:
To be considered authentically rare, a colored gemstone should exhibit the optimum hue, tone, saturation and distribution of color for its variety. Other aspects of the stone, including shape, cut, clarity and durability must add to its beauty and value. The stone should be free of enhancements, or in some cases, may be enhanced by heat only. Finally, even if all of the above qualities are present, if the stone is too tiny, it is not considered rare. Of these factors, color itself is the primary ingredient of cost.
Synthetic and Imitation Colored Gemstones:
A synthetic gemstone is made in a factory or laboratory, and has the same optics, chemistry and physical structure as its natural counterpart. Synthetic rubies, synthetic sapphires, synthetic star rubies and star sapphires were manufactured and appear in thousands of pieces of jewelry in the first 20 years of the 20th century. In the mid 1940’s, synthetic emerald was created. The 1970’s saw the creation of many more synthetics, including opal, turquoise, alexandrite and the quartzes. Note: synthetic diamond was created by General Electric in 1952. In 2016, multiple companies manufacture synthetic diamond, in sizes large enough to be used for engagement rings, stud earrings and other forms of fine jewelry. Historically, the introduction of all synthetics has never affected the demand for the natural gemstone. In 2016, even the most expensive synthetic colored gemstone is very inexpensive compared with its natural counterpart. Synthetic diamond is only about 25% less expensive than natural diamond of the same quality.
An IMITATION GEMSTONE is merely one that looks like the natural counterpart. The best example is glass, used for cutting transparent gemstones for 2000 years. Other imitations would include what gemology calls “assembled gemstones.” These are gemstones composed of several parts which are glued together. Opal doublets and triplets and diamond doublets are good examples seen frequently in the jewelry industry.