This is the second part in the Dos and Don’ts for Jewelry Care series. Below, please find cleaning instructions on a few of the more popular gemstones. Please contact me or another professional for any gemstone you don’t see listed. Remember better safe than sorry! Oh, one more thing, very few gemstones or precious metals can withstand long periods of soaking in a cleaning solution.
I also included a little information about taking care of watches since I see so many in disrepair. Watches can be beautiful, useful pieces of jewelry but they do need to be taken care of.
Why it is Important to Understand the Science of Cleaning Your Gemstones
Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. However, the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but many, many times harder than gems in the corundum (sapphire and ruby family).
Handle your diamond sparingly. Because diamonds are natural magnets for grease, they’re not easy to keep clean. Handling a diamond with your fingers provides enough oils from your skin (the type of “grease” that most affects diamonds) to alter the way your diamond looks. To be quite clear, don’t touch the table of the diamond with your fingertip. Really don’t touch the top or table of ANY gemstone with your ‘fingerprint’. That is a jewelry no-no. Jewelers around the world cringe when they see people do this.
Clean your diamond regularly. A simple plan to keep your diamond jewelry always looking beautiful is to soak the diamond in an ammonia-based household cleaner overnight, once a week. In the morning, remove the diamond from the cleaner and brush it with a soft, clean toothbrush (one that has not previously been used in any way, and that you reserve exclusively for cleaning your diamond) to remove any leftover dirt. Take extra care to brush the back of the diamond as this will be the area that has collected the most oil and dirt. Rinse with hot water over a strainer or a closed drain. Pat dry with a soft cloth.
Be aware that fragile settings and estate jewelry won’t take kindly to being scrubbed with a toothbrush, so use a soft touch.
Don’t use harmful solutions. Chlorine (as in household bleach) or abrasives (such as household cleansers or toothpaste) should never be used when cleaning diamonds, especially those set in jewelry. These erode some of the metals often used in diamond settings, and may loosen prongs, or even dissolve the metal completely. Toothpaste is not a choice for cleaning jewelry.
Sometimes an ultrasonic cleaner is necessary to remove encrusted dirt on diamonds. By sending high frequency sound waves through a detergent solution, ultrasonic cleaners cause vibrating fluid to remove accumulated dirt and grime. However, they can also shake loose stones from their mounting, so this method shouldn’t be used on fragile settings (or estate jewelry), and is best undertaken by a professional jeweler.
Sapphires and Rubies
Sapphire and rubies have a Mohs hardness of 9 so they are great stable stones for every day wear. Warm soapy water is always safe. Ultrasonic and steam cleaners are usually safe for untreated, heat treated and lattice diffusion treated stones. Untreated sapphire and ruby and even heat-treated sapphire and ruby are very durable. Fracture filled, cavity filled or dyed material should only be cleaned with a damp cloth. Remember, know what you have and what you have purchased.
Emerald is a 7.5 to 8 on the Mohs scale and has fair to good toughness. This makes emerald a stone that requires more care in wearing than ruby or sapphire. Emeralds can break and chip fairly easily, they have a little bit of a stability issue. Heat can damage emeralds, especially by extending existing fractures. Light and chemicals can cause the oils, resins and polymers used to fill surface reaching fractures to alter in appearance or to deteriorate. Some industry experts estimate that 90 percent or more of emeralds are fracture filled. Since the great majority of fashioned natural emeralds contain filled fractures, it is risky to clean them ultrasonically or with steam. Ultrasonic vibrations can weaken already fractured stones and hot steam can cause oil or unhardened resin to sweat out of fractures. Using warm, soapy water with gentle scrubbing is the safest way to clean emeralds. Do not soak emeralds.
Common substances like sand and dust are composed mostly of quartz, the mineral species that includes the purple variety amethyst. So, while amethyst is a great gemstone for use in jewelry, it should be treated with the proper care to prevent scratching and other damage. Amethyst rates a 7 on the Mohs scale and has good toughness, so it is suitable for all jewelry types. This includes rings as long as the wearer understands the limits of its hardness. Abrupt temperature changes can cause amethyst to fracture. Some amethyst color can fade with prolonged exposure to intense light. Amethyst can be safely cleaned with warm soapy water. Ultrasonic cleaners are usually safe except in the rare instances where a stone is dyed or treated by fracture filling. Steam cleaning is not recommended, and amethyst should not be subjected to heat.
Porous Stones such as Lapis Lazuli and Turquoise
Lapis is between 5 and 6 on the Mohs scale, depending on its composition. Its toughness is considered Fair. Lapis can be dyed or sealed with wax or plastic. The dye can come off with certain cleaners and the wax sealers can deteriorate when exposed to heat or solvents. Oil has fair stability and can be removed with heat. Warm soapy water is the safest way to clean lapis and start with a small, inconspicuous test area first because some dye treatments are not stable. Do not soak.
Turquoise ranks 5 to 6 on the Mohs scale and its toughness is generally Fair to Good. I love turquoise and own quite a bit of it. Taken care of, it will last a lifetime. High heat can cause discoloration and surface damage. It can be discolored by chemicals, cosmetics, and even skin oils or perspiration. Treatment can be very unstable and the turquoise color can change with temperature and age. Warm soapy water is safest and it should never be cleaned with steam or ultrasonic cleaners. Do not soak.
Pearls are not the most durable of gems, they are ranked 2.5 on the Mohs hardness scale. Most everyday items at home and in the office are tougher than pearls, so careless contact can cause damage to them over time. They are easily abraded and scratched. Chemicals are the primary threat. Apply perfume, makeup and hairspray before you put on your pearls. These items contain ingredients that can eat away the nacre, permanently dulling it. Many cleaning products contain chemicals such as ammonia and chlorine, which can pit gold alloys and quickly damage pearls. Chlorinated swimming pool water is quite hazardous. Pearls need a certain amount of moisture, which is why you should avoid storing pearls in an airtight or overly dry environment, such as a safety deposit box. Heat can also damage pearls. The best way to clean your pearls is with a soft damp cloth, ideally after each time you wear them. If you must, use warm, soapy water for occasional cleaning. DO NOT SOAK. If the pearls are strung, be sure the string is completely dry before wearing. Lay pearls flat, don’t hang them, it stretches and weakens the cord.
Mechanical watches are composed of many little coordinated parts that work together to keep the watch running. Parts are gently oiled and through normal wear and movement, the parts work together unless something breaks. Mechanical watches that sit for long periods of time without being used, can break when picked up and wound because the oils have dried out. No matter how handy you are, don’t attempt to perform watch repairs yourself. Mechanical watches need specialized parts for each particular brand, parts are not a one size fits all. Only an expert jeweler/watchmaker should be trusted to put your watch back into working condition. Make sure to give your watch a routine check to make sure the strap or bracelet is securely attached to the watch face. Wind your watch in a clockwise direction, preferably about the same time each day. Wind the watch when it is off your wrist to prevent undue pressure on the stem. Replace broken or scratched crystals immediately. Even a hairline crack can let dust and moisture into the mechanism. Water resistant watches can receive a quick cleaning with warm soapy water. If there is a leather strap, be careful. If there is a bracelet, don’t forget to clean it, those can get really dirty! If you watch is not water resistant or if you don’t know if it is, don’t take a chance, keep it out of water, clean it with a slightly damp cloth. Remember, water resistant is NOT waterproof.
Jewelry is meant to be worn, enjoyed and is supposed to last a lifetime!