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Care and Cleaning of Gemstones

Updated: Jun 28, 2022

Comprehensive guide on the care and cleaning of gemstones

including agates, jaspers, opals and pearls.

So you have a nice collection of stones. You have them identified and labeled. But do you know the the best way to care for them? Understanding the nature of the material you're using is as important as it's name. Each stone has different properties, a gems hardness on the Mohs Scale does not mean it is impervious to all exposure. Hardness is simply a stones ability to resist scratching. Some gems have characteristics that make they susceptible to certain types of exposure. For example, diamonds have the greatest hardness of any natural material. However, they can have inclusions and incipient cleaves that might have unfortunate reactions to heat or mechanical cleaning. Let's discuss cleaning and caring for your investment.

The first and most important step in caring for your gemstones is keeping them clean. Some of the most dangerous substances to gemstones are the ones you use everyday. Hairspray, body moisturizers, oils, chemicals can destroy some porous gemstones. Dust is also harmful. Microscopic particles of sand and other materials in dust can scratch some stones and over time dull the surface. While there is no "all-in-one" cleaning method for everything, mild soap and water is the safest approach in most cases. HOWEVER, soft porous materials such as turquoise, malachite, pearls, opals and gemstones with a Mohs scale of 4 or less can absorb water and all the minerals and chemicals (such as Chlorine and Fluoride) that are in it and remain in the stone ruining it. Distilled water is advisable for general cleaning. Opal. There are so many opinions about how to care for opal but let's look at the science. First, most (precious) opal is 6 -6.5 on the Mohs scale. the storing or occasional soaking of opals in water is not so they can absorb the water but to keep the water in the stone from leeching out. In fact, most precious opals contain about 5-6% water. As a result, opal may crack if subjected to very dry conditions or rapid changes in temperature. If you need to store your opal away for a period of time, simply place it in a padded cloth bag for protection and store it away. For longer storage periods, place your opal in cotton wool with a few drops of water, then into a sealed plastic bag just to be safe. Any extreme temperature changes can be very harmful so protect your opals from very high temperatures or low humidity extremes, such as boiling water or zero humidity bank vaults. Opals should NEVER be cleaned in an ultrasonic. Avoid cleaning with chemicals or cloths impregnated with chemicals. If your stone is scratched we advise consulting a qualified dealer to refurbish your stone. Turquoise. While 5-6 on the Mohs scale, which is pretty tough, most turquoise is very porous. Chemicals and body oils* can change the color. Exposure to high heat can alter color as well. Stabilized turquoise, which is most turquoise on the market, is tough but can be dulled or discolored when exposed to harsh chemicals such as those used in tumblers and cleaning cloths. Warm water and a mild soap are best for general cleaning then dry with a soft cloth. Scratches in turquoise can sometimes be repaired by a professional lapidarist. As always we suggest consulting an expert for this type of refurbishment. Turquoise should never be cleaned in an ultrasonic. These care instructions also apply to: Malachite, Azurite, Shattuckite, Amber, Sugilite. Lapis, Ivory, Coral and porous varieties of Variscite and Chrysocolla. *Note on oil patination on turquoise. Over the span of many years turquoise will change color as exposed to light and body oils. In the case of vintage turquoise the natural patination that has occurred from contact with skin over time is considered to add value and "Shinzui" (Japanese for spirit - life) to the stone. Agates and Jaspers. As agates and jaspers are basically quartz they are quite resilient. However each has it's won inherent characteristics. Always be careful and inspect your stones for cracks or inclusions that could absorb water or cleaning solutions. The use of ultrasonic is ok for most agates but again look for flaws that might absorb and hold the chemical solution. Alcohol is good for removing oils and dirt. We do not advise the use of ultrasonic cleaners or steam cleaners for Jaspers. Instead, simple and careful use of a warm, soapy water mixture with a soft cloth or a brush should be enough. Do not to soak a Jasper as it can be porous and can easily absorb other materials and get stains. Druzy - Druzy crystal formations require careful handling to avoid bruising the crystals. Most druzy is safe to clean in an ultrasconic but placing several at once can cause damaged as they vibrate together damaging the crystals. A soft toothbrush and mild soap and water is just as effective. A short soak in alcohol to remove oils and stubborn dirt is good too! Diamonds, Rubies, Sapphires. The hard gemstones, from 7-10 on the Mohs scale can be cleaned with alcohol to remove oils and dirt. Dip in alcohol wipe and then wash with mild soap, rinse and dry with a soft cloth. Generally the use of an ultrasonic is safe (be sure to consult a qualified jeweler). Tourmalines - While 7- 7-5 on the Mohs scale tourmaline is heat sensitive. It is advisable to not use an heated ultrasonic to clean them. They are best cleaned with warm, sudsy water and a tightly woven microfiber or other soft cloth. Some other gemstones vulnerable to heat and light are: Tanzanite, Amethyst, Topaz, Carnelian, Kunzite, Moonstone, Emerald, Labradorite, Morganite, Zircon, Coral, Zoisite, Aquamarine and Citrine. Care instructions for these should be approached as stated above. Note: You can replace your chemical ultrasonic fluid with distilled water and a drop of mild soap which would be safe to use on the gemstones listed above. Note: NEVER put strung gemstones in a ultrasonic machine. Pearls. Pearls rate a paragraph all to themselves. Due to the nature of pearls special steps should be taken to care for them. Note1,Contrary to popular belief, the acidic oils and perspiration from human skin can damage the surface of pearls. NEVER use an ultrasonic cleaner, the vibration can damage the nacre. Chemicals to avoid include, Chlorine (swimming pools or jacuzzis), bleach, ammonia, baking soda, laundry detergent, all chemical cleaners. Foods that could damage your pearls include any with oil or acids, avoid fruit juice. Always keep pearls away from heat. Direct long exposure to sunlight or intense halogen lights, can fade natural as well as treated colors. How to clean your pearls: Wet your hand and glide your strand gently to dampen the pearls. Do not put them directly in water. Place the strand on a clean towel, press & squeeze (don’t wring) the towel and remove the moisture along with the oils and perspiration that has accumulated on the pearls. Periodically, use a dilute natural soap solution that has been rung out in a towel to roll and squeeze the pearls. Then use a fresh, damp towel and roll the pearls in them to remove the soap. When clean, the pearls will feel smooth and have their luster once again. If you have a pearl cloth, press the pearls in it for an extra cleaning touch. Remember to clean your pearl earrings too. Store in a soft cloth bab, Never store in plastic bags, they contain chemical that can harm the surface of the pearl. 1 information credit: Betty Sue King, Pearl Goddess Pearls. On cleaning strung gemstones. Gemstones should never be completely submerged or soaked in water. In the case of silk the moisture absorbed in the string will cause it to swell and deteriorate. Synthetic string, while water resistant, can trap water in the bead causing damage and discoloration. Final notes on cleaning and care. There a so many cleaners on the market today but none are a one size fits all. Be very careful when using these. Warm water and mild soap and a toothbrush are often all you need. A toothbrush is a excellent tool for cleaning most gemstones with a hardness over 5 on the Mohs scale (never use on pearls). HOWEVER, it is extremely important that you use only a "SOFT" bristle brush, medium or hard bristles can scratch your stones. Apply your perfumes, colognes, and hairsprays before you put on gemstone jewelry. Not only will these chemicals reduce gem brilliance, the ability to return light, they can be highly destructive to some gems, such as pearls, which react violently to acid and alcohol. For a detailed guide to gemstones care visit:

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