No matter how careful we are, all gemstones are susceptible to wear and tear. Unfortunately, over time their natural beauty can appear to diminish, and this can be a result of many factors, including scratches, a buildup of dirt, or even something inherent within the makeup of the gem itself.
Thankfully, the natural properties of your gem can often be restored with a little bit of cleaning. We’ve touched on jewellery care before on the Gemology Hub, but we’ve received many a request to go into more detail on the pros and cons of different cleaning methods, and care relating to specific gemstones. This is by no means an exhaustive list, but if you’re looking to put some of the sparkle back into your older pieces, this guide will help you get started.
JEWELLERY CARE AND STORAGE
Cleaning your jewellery is a normal part of being a gemstone collector, but prevention is better than cure, and there are some steps you can take to keep your jewellery looking its best for longer.
Always put your jewellery on last when you’re getting ready, as perfume, aftershave, hairspray and the like are very bad for most gemstones and can reduce their brilliance.
Always take your jewellery off while washing up, cleaning, gardening or doing any manual work. The chemicals in swimming pools are to be avoided too, so leave your jewellery in a safe locker or at home.
Always remember to remove your jewellery when exercising and working out, or if you’re playing sports.
When you are not wearing your jewellery, keep your gemstones away from extreme heat sources and bright sunlight, such as on windowsills or near radiators. Avoid leaving pieces in humid areas too so try not to leave your jewellery in the kitchen or bathroom.
Always put jewellery away if it’s not being worn. Our pieces all come in soft pouches because we believe the best way to keep them safe is to wrap them individually.
If you do want to keep your jewellery together in a box, just make sure the pieces can’t touch, or they may scratch each other. Pay particular attention to this if travelling with your jewellery.
When cleaning multi-gem pieces, always protect the most delicate element. A Pearl accented with Diamonds will need to be cleaned as a Pearl piece, even though Diamonds can take much tougher methods of cleaning.
Don’t use harsh cleaning chemicals such as bleach or anything that contains ammonia, as many gems will react badly with them.
When it comes to cleaning your jewellery at home, the golden rule is that if you’re not sure, don’t risk it. Never commit to a cleaning method until you are sure it is safe for your gem, and when you’ve found one that works, stick with it.
THE IMPORTANCE OF MOHS SCALE
When it comes to cleaning, a good piece of advice regarding the Mohs scale is to remember that a gem can be scratched by any gem with a higher hardness and will scratch any gem with a lower hardness. Gems with the same hardness won’t scratch each other. This is important because household dust can reach up to seven-and-a-half on the scale because it contains a lot of silica and Quartz. It’s important to use a clean, lint-free microfibre cloth when working with your jewellery, and you must always pay attention to the softness of a brush before you use it on your gemstones.
Devised by the German mineralogist Friedrich Mohs, this scale is a means of grading the relative hardness of minerals. Using ten common minerals, Mohs put them in order of their 'scratchability', placing talc at 1 and Diamond at 10. Quite simply, each mineral will scratch the ones below it, and be scratched by those above it.
- 10 - Diamond
- 9 - Corundum (Ruby and Sapphire)
- 8 - Topaz
- 7 - Quartz
- 6 - Orthoclase
- 5 - Apatite
- 4 - Fluorite
- 3 - Calcite
- 2 - Gypsum
- 1 - Talc
TREATMENTS AND INCLUSIONS
Be very careful cleaning treated gems. Common treatments include heating, oiling, fissure filling, dyeing and coating, and special attention must be paid to these. Always err on the side of caution if you don’t know which treatments your gems have received, and never risk any of the harsher cleaning methods like ultrasonic or steam cleaning. Inclusions are made of a different material to that of the gem, and when under extreme heat or cold they may expand or contract at a different rate to the rest of your stone, causing it to fracture or even shatter. Inclusions can also break the surface of a gemstone, which could let harsh cleaning solutions in and cause irreparable damage.
If this seems like a lot to remember, don’t worry! We’ll start with a cleaning method that’s safe for almost any gem, and we’ll discuss how to clean some of the notable exceptions later on.
WARM SOAPY WATER AND A SOFT BRUSH
Helpfully, the vast majority of gemstones can be cleaned using warm soapy water and a soft brush. All you need to do is mix a little mild detergent like unscented washing up liquid with some warm water in a bowl.
Ensure the water is not too hot, as some gems don’t react well to a sudden change in temperature. Make sure you’ve got a nice soft brush you can use to cleanse the gemstone. While a tough brush is unlikely to scratch a Diamond, it could scratch softer gems such as Fluorite and Apatite. Whatever your choice of brush, we’d recommend using a brand new one, so there’s no chance of any previous cleaning product damaging your gem.
Let your jewellery soak in the warm soapy water for a few minutes, and then begin to brush gently. On faceted stones, while it’s easy to access the top table of the gem, don’t forget to also clean the pavilion – the underside of the stone. If you’re having trouble getting to it, soft cotton buds may be able to reach the area. If the dispersion of your gem, which is its ability to return light, isn’t at its best, this is likely why. Grease and grime on the underside of a gemstone interferes with the way light passes into and around your gem, dulling its sparkle. If your gem is cut en cabochon, don't worry about cleaning the back. This may reduce the optical properties of the gem rather than enhance them. For tough grime, you can let the jewellery soak for a little longer in the warm water, and repeat the process as needed.
When you finish cleaning, make sure you wash off all the soapy residue. Rinse the piece in running water but try to match the temperature of your original warm water if you can. Shake off any remaining water, and use a soft lint-free microfibre cloth to dry and buff the gem and metalwork. Make sure it’s a clean cloth, a dusty or dirty cloth could scratch some of your gems. Hopefully, this process will leave your gem looking as good as new. If not, you can repeat the process until the dirt is completely removed.
GEMSTONES USUALLY SAFE FOR THIS METHOD: Alexandrite, Amazonite, Amethyst, Ametrine, Andesine, Apatite, Aquamarine, Carnelian, Chalcedony, Citrine, Diamond, Diopside, Emerald, Fluorite, Garnet, Goshenite, Heliodor, Howlite, Iolite, Jade, Kunzite, Kyanite, Labradorite, Lapis Lazuli, Malachite, Moldavite, Moonstone, Peridot, Petalite, Rainbow Moonstone, Rhodonite, Ruby, Sapphire, Scapolite, Sillimanite, Sodalite, Sphene, Spinel, Sunstone, Tanzanite, Topaz, Tourmaline, Turquoise, Zircon.
Ultrasonic devices clean gemstones and jewellery by creating high-frequency sound waves that cause bubbles to form in the liquid surrounding your piece. As these bubbles burst with high pressure, they dislodge dirt and grime from the gem and metalwork, leaving pieces looking clean and fresh. It sounds like a simple and easy solution, but there are many caveats with a tool of this complexity. If your gem has been treated in any way, it’s best to avoid this method. Almost all Emeralds are treated with oil, for example, and heat treating is common across a wide number of stones. Porous and especially delicate gems like Opal and Pearl should be kept away from this method too.
Always follow the manufacturer's instructions regarding how long you should leave your jewellery in the cleaner for, and at what temperature. Never exceed these guidelines as it may damage your jewellery.
Use the recommended cleaning solution as many have been specially formulated to work in ultrasonic technology.
Make sure your cleaner comes with a basket that sits within the device. Your jewellery and gemstones should not directly be touching the sides or bottom of the cleaner.
Always check that the cleaner hasn’t knocked any stones loose before you dispose of the cleaning solution.
Some gems should never be cleaned using this method, regardless of treatment, and we’ve listed some of the most common ones below. This can be down to their relative softness, or even their tendency to split across their cleavage plane under certain circumstances.
GEMSTONES YOU SHOULD NEVER CLEAN ULTRASONICALLY: Amber, Andesine, Apatite, Chrysocolla, Chrome Diopside, Coral, Emerald, Fluorite, Iolite, Kunzite, Labradorite, Lapis Lazuli, Malachite, Moonstone, Opal, Pearl, Peridot, Sunstone, Tanzanite, Topaz, Tourmaline, Turquoise, Zircon. To be safe, avoid any gemstone that has been treated, appears heavily included or is damaged in any way.
In steam cleaning, the high temperature and pressure combine to quickly blast away the dirt on a piece of jewellery which is particularly efficient at removing oil and grease. Temperature, as we’ve already touched upon, is another important factor in jewellery cleaning, so steam cleaning can pose many risks. There’s always the possibility of thermal shock when the temperature of a gemstone changes suddenly, the worst outcome of which is that your stone will split. These issues are often because of inclusions within the gem, rather than the gem itself, especially if there are tiny pockets of moisture within the stone.
Steam cleaning at high pressure is a highly dangerous and specialised task, and the vast majority of you will not own a professional steam cleaner. So if you’re going down this route, just make sure your chosen jeweller understands the process and the dangers.
You need to pay more attention to detail when it comes to cleaning certain gemstones, we've described some of the more common ones below.
Opal is one of the most spectacular and colourful of nature’s treasures, and special attention must be paid to keep it looking its best. As well as avoiding ultrasonic and steam cleaning, be wary of completely submerging your Opal in water too. Some Opals are doublets or triplets, where the Opal has been combined with another gem or even a synthetic material to strengthen it for use in jewellery. Soaking in water can eventually cause these layers to separate.
Warm soapy water is still the best method for cleaning Opal, but unless you’re sure it’s one solid Opal, don’t submerge it. Instead, moisten your soft lint-free microfibre cloth and buff the gem this way. Use a dry part of the cloth to remove any moisture that remains. Because Opal doesn’t like sudden temperature changes, use water that’s room temperature too.
Keep Opal well away from any extreme heat sources as they contain a small amount of moisture, and if this dries out you can get surface cracks known as crazing. If you fear your Opal is losing moisture, sometimes wrapping it in moist (but not soaking) cotton wool and putting it in an airtight bag can help. Check it regularly and re-moisten the cotton wool if it has dried out. Opals react badly to acid and alcohol, so be especially careful to keep them well away from any household cleaning products, aftershaves and perfumes, etc.
Amber is fossilised tree sap left over from ancient forests, so like Pearl, it is also organically formed and needs special care and attention. But while a Pearl can develop in just a few years, Amber is millions of years old.
To put that in perspective, if we say that on average a Pearl takes four years to form and that a piece of Amber is around 40 million years old, then if we reduce the ratio to say that the Pearl was formed in one second, then the Amber would still take almost four months to form! Not something you want to spoil by using the wrong cleaning product.
The warm soapy water method can still be used with Amber, but as with Pearls don’t submerge the Amber and only use a small amount of mild detergent. Moisten the soft cloth and gently rub the gem, drying immediately. If you do need to use a brush for more stubborn dirt, make sure it’s incredibly soft as Amber is only a 2 to 2.5 on the Mohs scale, meaning almost anything will scratch it. If you have multiple gems in a piece, try to clean and dry them one at a time, as prolonged moisture on the surface can cause Amber to lose its polish and can cause cloudiness. If you feel your piece has lost its polish, you can rub in a little olive oil or almond oil with a soft cloth and, again, dry it off.
Pearl is an unusual gem as it is created organically by molluscs (usually oysters) under the sea. This most famous and glamourous of gems is also, relatively speaking, in need of the most special care. It comes in between 2.5 and 4.5 on the Mohs scale which is much softer than most gems, so always store your Pearls away from your other jewellery. Be aware that your fingernail is hard enough to mark the surface of some Pearls.
Amazingly, some Pearl advice states you should try not to let Pearls touch the skin, as even perspiration and oils from our skin can cause problems. Don’t let this stop you wearing the Pearls as you wish, though, and if they do come into contact with your skin, wipe them down with a very soft clean cloth when you take them off. Always put your Pearls on last when you’re getting ready, as they’re vulnerable to all sorts of cosmetic products.
The warm soapy water method can be slightly modified to work well with Pearls. The gem is incredibly soft and porous, so despite its oceanic origins, it’s recommended that you don’t dip them into any liquid. When preparing your soapy water, only use a tiny amount of mild detergent. Moisten a very soft and clean lint-free microfibre cloth and wipe your Pearls carefully and gently. If there’s any remaining dirt, use a very soft brush to dislodge it.
Dry your Pearls immediately with a dry portion of your cloth. If the Pearls are drilled and threaded, on a necklace for example, take care to get as much moisture away from the threading material as you can. Never use heat to dry the piece, but you can blow gently to remove any remaining moisture. It’s worth having threaded Pearl pieces restrung every few years, and don’t take them anywhere near a steam or ultrasonic cleaner.
Warm soapy water is safe to use with Kunzite to keep it clean. Whether or not the stone has been treated, it can begin to lose its beautiful colour with prolonged exposure to bright sunlight. Kunzite has long been known as the evening gemstone for this reason and looks just stunning in more subtle lighting. Keep it out of extreme heat and avoid sudden temperature changes too, and when not wearing it always keep it in a jewellery box or pouch. With diligent care, your Kunzite will give you a lifetime of sparkle, beauty and colour.
As we’ve already mentioned, it’s not unusual for an Emerald to have been oiled to improve its appearance. This is a common Emerald treatment and also one that has been documented as far back as Ancient Egypt. Some estimates place 90% of the world's Emeralds in the oiled category.
If you feel your Emerald has lost some of its character and shine, talk to a professional jeweller about having it re-oiled. To do it properly requires specialist equipment and the usage of a specific oil, such as cedar oil, that has a similar refractive index to Emerald. There are some home methods for re-oiling listed online, but many of them could damage your gem irreparably.
For general cleaning, the warm soapy water method discussed earlier is fine, but don’t soak your Emerald for long. Avoid ultrasonic and steam cleaning.
Drusy gemstones are simply spellbinding and offer a very different look to many other gems, but as they are essentially made up of lots of tiny little crystals, extra special care must be taken when cleaning. The warm soapy water method is fine to use with Drusy, but don’t use a cloth. Choose a very soft brush when it comes to scrubbing, and use a gentle motion to work away any dirt that may be on your gem. You can dip the Drusy if necessary, but don’t keep it in the water for long.
Once you’ve finished cleaning, rinse briefly under running water to remove soapy residue and shake off any moisture. You can use a hair dryer to ensure the piece is totally dry, which will stop any specks or spots forming where the moisture has evaporated. Use a very low heat though, or even cool air if your model has this feature.
You can use a soft cloth and a little soapy water to clean your precious metals like gold and silver, and this will work in most cases. Some home methods use products like vinegar, lemon juice and baking soda diluted in water but while these may work for purely metal pieces, you need to keep the vast majority of your precious stones away from those chemicals. Bear in mind too that metalwork can be plated and harsh cleaning can eventually remove that. There are specific cloths on the market that are great for metalwork cleaning, and have the cleaning solutions embedded into the cloth, reducing mess. In most cases, buffing the metal at the same time as cleaning your gems will keep it looking as good as new.
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