Despite the immense popularity of diamonds, colored gemstones have always been among the most popular and expressive forms of jewelry. The bright colors of colored gemstones give each a unique personality, and personal tastes in color often dictate preferences for particular stones.
Long before diamonds were found worthy of jewelry, people revered sapphires, rubies, emeralds, and all manner of colored stones. In addition, almost all colored gemstones were believed to have special powers or cure specific illnesses. There was a time when a collection of different gemstones was the equivalent of a medicine cabinet!
Today, gemstones are still loved for their beauty and personality. The precious gemstones - sapphire, ruby, and emerald - are among the most prized. Precious gemstones of good size and quality are so rare that a natural, unenhanced, strongly colored stone can be worth as much per carat, or more, than a diamond of comparable quality.
Given the extreme cost and rarity of such stones, jewelers developed ways to enhance the appearance of more common stones, both precious and semi-precious. For hundreds of years, it has been common practice to heat gemstones to bring out their best color. This is viewed as simply extending what nature started, since it is the heat and pressure within the earth that gives gemstones their color.
There are many other common types of treatment to enhance the beauty of colored gemstones. Emeralds are often oiled and waxed to protect them and to hide fine lines that naturally occur in the stone. Some sapphires have their blue color enhanced using diffusion, a chemical process. Certain stones are treated with radiation, again mimicking the processes of nature. All these practices are standard in the jewelry industry; in fact, enhancement is so common that good quality unenhanced stones often come with a certificate stating that fact.
Other than the oil on emeralds, which can last for years before needing replacement, any quality enhancement is permanent and should not require special care. With emeralds, you should simply be careful not to clean the stone too vigorously or you might remove the layer of wax or oil, changing the appearance of the stone. If this happens, bring it to your jeweler to have the layer reapplied. Bringing your emerald in for a cleaning and re-oiling on a regular basis will help keep it looking its best.
Synthetic or "lab-created" stones, on the other hand, are grown using the same ingredients as the natural stones. They are chemically identical to natural stones, but more affordable, and its easier to get a large, well-colored lab-created gem than a natural one. Lab-created gemstones frequently have fewer "inclusions", the internal flaws common in precious gems. With technical advances, many high quality lab-created stones can only be differentiated from a natural by a trained professional. Almost any gemstone can be made in a lab, but the precious gemstones - emeralds, rubies and sapphires - are the most common.
Included in each gemstone description in this section is its Mohs' Hardness Rating, based on the system developed by Austrian mineralogist Friedrich Mohs to compare the relative hardness of different minerals. The scale ranks from softest (talc, with a ranking of 1) to hardest (diamond, which is the only mineral ranked 10). Hardness is the resistance to scratching. When various minerals are scratched against each other, any mineral with a higher hardness ranking will mark any mineral with a lower ranking.
Only three colored gemstones are considered precious. These are the emerald, sapphire and ruby, which have retained their prized positions among jewels due to their extraordinary colors and extreme rarity. Precious gemstones with good color and large size are very hard to come by. Because of their rarity, it is common to use stones with inclusions and blemishes in jewelry.
A semi-precious gemstone includes any gemstone other than sapphire, emerald or ruby. The value of semi-precious gemstones can vary depending on the availability of the mineral; natural black opal, for example, is hard to come by and more valuable than most other semi-precious stones. As a rule, however, semi-precious stones are always more plentiful than precious stones. That makes it easier to find large, well-colored, very clean stones appropriate for jewelry. In addition, the wide range of colors available makes semi-precious stones the choice for people who want to create their own look with their jewelry.
Keeping gemstone jewelry clean is essential to its beauty and sparkle. You must use an appropriate cleaner to avoid damage to stones or settings.
Cleaning gemstones is easy. Simply soak the piece in a bowl of warm, soapy water for several minutes. Then use a soft, non-metallic brush to remove any grime. If you use a jewelry cleanser, make sure it is non-abrasive. Don't use harsh chemical cleaners, and be careful when cleaning the item in the sink because it can end up down the drainpipe. Also, keep in mind that some gemstones may have been treated or enhanced by heating, oiling, irradiation or diffusion. Heated and irradiated stones generally don't require special care when cleaning, but diffused stones could become lighter if scrubbed too hard.
You can use commercial jewelry cleaner in its container. Be sure to read the instructions on what gemstones can be used in the solution. You can use a small, soft brush to remove residue.
Ultrasonic cleaners clean jewelry using vibration in a cleaning solution to loosen dirt. That vibration can be very harmful to most gemstones. The only gemstones suitable to be put in an ultrasonic cleaner are diamonds, rubies and sapphires. Just think red, white and blue for the ultrasonic cleaner as an easy way to remember the only three gems you can put in that unit.
Because of their unique characteristics, opals and emeralds require special care and treatment.
For opals, do not use a commercial cleaner or an ultrasonic cleaner. Clean an opal using mild, warm sudsy water (1 part to 1 part) and be gentle. Rinse in clear, warm water and gently pat dry. Since opals have a high-moisture content, you need to keep them hydrated by storing them with a moistened cotton ball.
Emeralds usually have a high number of internal inclusions called "jardins". Consequently, emeralds are fragile and very susceptible to damage from a knock, heat or vibration. Also, the oil on an emerald can be stripped away by cleaning, making the emerald change appearance. If this happens, simply bring it to your jeweler for re-oiling.
Natural gemstones may have been color and/or clarity treated by various enhancement processes including, but not limited to: heating (generally); oil/wax/resin (emeralds, opal, tourmaline, turquoise); diffusion (sapphires, rubies, topaz); irradiation (some color diamonds, topaz, tourmaline, morganite); fissure-filled with a glass-like by-product (rubies); or dyed (chalcedony, sugilite). Treatments may not be permanent and/or may require special care. Exposing gemstones to extreme heat, excessive light, chemicals and ultrasonic, steam or abrasive cleaning should be avoided. Generally, gemstones should only be gently cleaned by rinsing in warm water and drying with a soft cloth. Proper care is required in jewelry repair as extreme heat can damage gemstones and/or treatments.