What is a gemstone?
The majority of gemstones are minerals (important exceptions - pearls and coral are of animal origin; jet and amber are vegetables). These minerals have been crystallised as a result of high temperature and pressure exerted by nature on the elements that form the Earth's crust.
Of more than 3,000 minerals found on Earth, only small percentages qualify as gemstones due to their beauty, durability, colour and rarity. The most sought after are transparent gems, drops of pure colour cut from single crystals. Until recently, gemstones were divided into precious and semi-precious categories. This is no longer true as gem discoveries have added new varieties to the traditional precious category of diamond, ruby, emerald and sapphire. In fact, some of the more unusual gemstones command higher prices than traditional precious stones because of their beauty and rarity. For example, fine jade and fine opal could be more valuable than lesser quality diamonds or emeralds of the same carat weight.
The selection of fine quality gemstones includes such stones as alexandrite, amber, amethyst, aquamarine, chrysoberyl, citrine, emerald, garnet, iolite, jade, kunzite, lapis lazuli, moonstone, opal, peridot, ruby, sapphire, spinal, tanzanite, topaz, tourmaline, tsavorite, turquoise and zircon. Each of these gemstones has a particular charm, colour and identity.
What determines the value of a gemstone?
There are several factors that determine the value of a gemstone.
Colour: The strength and purity of a gemstone's colour is of prime importance. There is no established right or wrong colour and there are literally thousands of shades. Therefore, you should make your selection according to your own personal taste.
Cut: The cut of a gemstone is of extraordinary importance. The proper cutting emphasises the richness of the gemstone's inherent colour, which is the focal point of the gem's beauty that attracts the eye.
Clarity: While the clarity of a gemstone is an important feature, it is equally important to remember that completely flawless gemstones are extremely rare. Inclusions are inherent to practically every gemstone and are nature's way of adding variety and individuality to a gemstone. Even the most expensive can contain some inclusions.
Carat Weight: The size or weight of a gemstone also affects its value. Remember, 1.00ct of gem weight equates to 0.20 grams but it is not a quality rating as in gold.
Common Gemstone Terms
Gemstone: is a mineral or other natural material that is beautiful enough, durable enough, and rare enough, to be used for personal adornment or for the embellishment of personal possessions. This is the modern definition of a gemstone. Non-mineral gemstones include: coral, pearl, amber, ivory, these examples are all organic gemstones.
Natural: the term "natural" is placed before the name of a gemstone when there is a synthetic version of the stone available. The term gives no indication whether the gemstone has been treated or not, it simply indicates that the gemstone is of natural origin. Examples: Natural Pink Sapphire (ie. a synthetic is available), Synthetic Pink Sapphire (indicates it is not natural), Demantoid Garnet (no synthetic is produced so the term natural is not used).
Treated: Gemstones can undergo various treatments to enhance their value. These gemstones are still natural gemstones. Example: Natural Blue Sapphire are heat treated, Natural Emerald are oiled.
Synthetic: A synthetic 'gemstone' is a man-made material having the same chemical composition, crystal structure, and most physical properties of a (natural) gemstone. For example, Synthetic Ruby or Synthetic Diamond. Synthetic gemstones are sometimes called "lab-created", "created" or "man-made".
Imitation: Imitation gemstones are predominantly human-manufactured products that only visually resemble the gemstone they are intended to imitate. Examples: glass and composite stones (which are made from several components), have been used to 'imitate' gemstones. A gemstone can also be an imitation of another more valuable gemstone, eg a Blue Topaz may imitate an Aquamarine, or a Rubellite Tourmaline may imitate a Natural Ruby, and they are all natural gemstones. Imitation gemstones are sometimes called simulants.
Enhancements of Gemstones
Enhancement of gemstones refers to treatments or processes that improve the appearance, durability or value of a gemstone. Today many gemstones have been enhanced by countless methods to improve the natural properties of gemstones. Some treatments and processes are fairly simple where others are more complex. Some gemstone enhancements are less durable that others, meaning that the appearance of the gem may change over time.
Additionally, heat must never be applied to a treated stone, it should always be removed from the setting before any repair work is completed. A customer must advise their jeweller if a stone is treated so that any work being completed on a piece of jewellery is adequately handled. Failure to advise the jeweller may result in damage to the gemstone and further costs for the customer, as a jeweller will not be liable if any treatments were not declared.
Types of enhancements are, but not limited to, bleaching, coating, dyeing, filling, flux heating, heating, impregnation, lasering, oil/resin infusion, irradiation and waxing/oiling.
Caution must be exercised when cleaning or using ultrasonic cleaners. Excessive cleaning and the use of ultrasonics may affect the treatment that has been applied to certain gemstones. For example, most emeralds are oil or resin impregnated and the use of ultrasonics may remove this treatment or expand existing fractures. Organic porous gemstones such as opals and pearls should under no circumstances be exposed to ultrasonics. If unsure if a gemstone can be cleaned in an ultrasonic, do not use an ultrasonic.
Gemstones such as opal, pearl, coral, amber and turquoise are heat sensitive. It is advisable not to leave them sitting in hot sunlight, near heaters or in hot cars. Once an opal begins to craze, it is irreversible. Craze occurs when the water in opal dries too quickly.
Care and Storage of Gemstone Jewellery
Jewellery containing nonporous gemstones should be periodically cleaned and checked for wear and breakages. You can clean it yourself with lukewarm, soapy water but your JAA jeweller can professionally clean it and add that extra sparkle. It is safe to do a little gentle scrubbing with an old toothbrush or other soft brush, gently scrub behind the stone where dust and soap can collect. Then rinse and pat try with a soft cloth. Be careful not to scrub highly polished metal surfaces as the slight abrasive action of the brush may produce a dull effect on the metal. To remove heavier deposits of dust and dirt a soaking may be necessary.
Jewellery containing gemstones should be stored in a cool, dry place. Gemstone-set jewellery should be stored in separate compartments in a jewellery box or soft pouch. This avoids damage caused by scratching and rubbing. Never store jewellery in paper, cardboard or cotton filled boxes. For best result, place the items in a sealed airtight plastic bag or sulphur free tissue paper prior to boxing and wrapping.
Organic gems such as pearls, opals, amber, malachite and coral require special care and storage because they are porous. To clean them, simply wipe clean with a soft cloth. Strands should be restrung if the cord frays or stretches so that individual pearls move. Keep away from dirty water and oils to avoid discoloration.
Some gem varieties might be damaged with a sharp blow. When removing your rings, don’t pull them off by the gemstone: this won’t damage the gem but it can, over time, stretch the metal that holds it in place, making the setting less secure.
Always take your jewellery off before applying moisturisers and other skin creams, sun screen, dyes, hairsprays and perfumes. Avoid gemstone jewellery coming into contact with abrasive soaps, chemicals, detergents, bleaches, ammonia or alcohols as these chemicals will cause discolouration and irreversible damage.
Jewellery should always be removed prior to washing, bathing, doing dishes, household chores, strenuous activities, exercise, sport, swimming (both ocean saltwater or chlorinated pools), to prevent scratching, denting or loss of gemstones. Remove all jewellery before going to bed to avoid damage or breakage.
Soft and brittle gemstones such as opal and pearls should not be used in jewellery that may be subject to hard wear such as rings that are worn on a regular basis. If set in rings, settings should be designed to protect the stone as much as possible. Harder gemstones are less likely to be scratched but are still subject to chipping and fractures. Softer stones are much safer in earrings, pins, pendants or bracelets.
Sharp corners on stones shapes such as pear shape and marquise are especially susceptible to breakage and should be protected by the setting to eliminate the possibility of damage.
The royal purple amethyst has one of the most interesting histories of any gemstone. Ever since mankind first discovered amethyst around 3000 B.C., this accessible gemstone has been believed to possess a wide variety of amuletic qualities and properties.
Traditionally associated with royalty and luxury, the amethyst has become the February birthstone in this century. Amethyst is tough and durable, wears well, and gives modern men and women the look of royalty at very affordable prices.
Aquamarine is tough, durable and takes an excellent polish. Aquas can be worn in rings and bracelets with minimal risk if the settings are designed to protect the gems. Avoid steam cleaning or excess heat. Clear stones, called eye-clean, are free of inclusions to the naked eye and can be worn under most conditions.
Recently designers have begun combining aquamarines with golden citrines, emeralds or tsavorite garnets, sapphires and pink tourmalines to provide fresh fashion colour palettes.
You don't have to be a sailor or a March-born baby to enjoy the beauty and sparkle of aquamarine. It's a year-round treasure of a gem.
Aquamarine, the lovely blue-green member of the beryl family, has been used in jewellery since the third century B.C. and is one of the most fashionable gemstones today. For hundreds of years it was called "The Sailor's Stone," due to its sea-like colours, ranging from a pale sky blue to a deep blue-green, and was thought to protect sailors and people traveling over water.
As a January birthstone, Aquarius Zodiac stone, and the second wedding anniversary gem, garnet provides a versatile family of affordable gems that can be enjoyed year-round. Garnet is actually the group name for a family of gemstones that come in every colour except blue. They're beautiful, durable, and most garnets are very affordable. The name ‘garnet’ comes from the Roman word granatus meaning ‘seed’ as the gems were thought to resemble pomegranate seeds. The most common garnets are the red to red-brown varieties that people know best. Red garnets can show almost as much fire as rubies.
Though garnets are tough, like all gemstones, special care must be taken, as some varieties can chip. For jewels worn often, like rings, look for settings that protect the gem with metal." Also avoid steaming, abrupt temperature changes, and acids, because they might damage gems. Ultrasound or warm water with mild detergent are recommended for cleaning.
Just as diamonds have become the gem of romance, ruby has been the gem of passion and the heart's desire since the dawn of time. Because of its lovely red colour, ruby has been associated with the heart, the blood and the centers of passion throughout its history
In modern times, ruby has become the July birthstone, fifteenth and fortieth anniversary stone, and the gem of Cancer. Sharing the same physical properties as its fellow corundum sapphire, ruby's vibrant colour and durability make it a popular choice. These days, ruby-lovers are in luck. New sources of supply in India, Africa Vietnam and Thailand have made lovely rubies in all sizes and colours more readily available than in previous years.
Rubies come in many shades of red. Rubies tend to be priced by colour. The closer a gem is to the vivid red 'pigeon's blood' colour, the higher the price. Many rubies are enhanced by heat treating to improve colour, but the colour is stable after treatment and does not require special care. Some rubies have fissures or surface breaks that are filled with a glass-like by product of the heating process. These stones do require special care in cleaning and wearing, but they are generally more affordable.
One of the most exciting recent developments is the entry of fancy coloured sapphires into the jewellery realm. Fancy coloured sapphires are those colours of corundum that are not considered ruby or blue sapphire. They can come in green, violet, purple, yellow, gold, pink, light orange, and the famous pinkish-orange colour known as Padparadscha, named for the Hindu word 'lotus.' Many are affordable and available in large quantities.
To improve a sapphire's colour and clarity, it is often subjected to controlled heating. This is a permanent enhancement that is well accepted by jewellers. Sapphire is second only to diamond in hardness, which made them difficult to facet until modern cutting technology was developed. Cut stones are available in sizes up to 10 carats, with one to five carat gems most common.
Sapphire is remarkably tough and safe in most types of cleaning. However, it should be given the same care as any other precious gem to avoid scratching. Most damage to sapphires occurs from rubbing them against another sapphire or diamond, careless handling and hard knocks directly to the stones.
With the magnificent range of sapphire colours available at all price levels today, sapphire is not just the gem of wisdom, it's a wise buy as well.