Diamonds are rare, beautiful, expensive. They are "girls' best friends" and (not only) boys' good investment. Here is the overview of what should we know about diamonds to make a right choice whatever our purpose is. Part three describes the diamonds common treatments and diamond jewellery cleaning.
Gabriel Levin-Cafrir (M.Soc.Sci), second generation diamantaire, graduate of the Center of Gemological Studies under the leadership of one of the leading Graduate Gemologists of Israel - Eli Dori, specialization - Diamond Expert (“Diamond Grading & Evaluating” diploma), at Diamond Exchange, Ramat Gan, Israel. The evaluation of diamonds is based on the G.I.A (Gemological Institute of America) standards. Practiced in Israeli commpany “Keren Or”. Works in jewellery and gemstones sales sphere (family business), consults, does lecturing.
Diamond Common Treatments
There are many terms such as “diamond treatment” or “treated diamond,” or “enhanced diamond”, but they all means one thing – the diamond that called that way is no more the same as it was once formed. It is now modified.
A relatively small percentage of gem-quality diamonds are going through the treatment process. While treatments can increase a stone’s colour or clarity grades, the presence of such enhancements may affect the diamond’s value – particularly if the price reflects its appearance after treatment.
The modification affects only colour and clarity (as I mentioned earlier) and can be permanent or nonpermanent. If we speak about cut and carat weight – the stone has to be recut and this is another story to tell.
Treatments for Colour enhancing
- Irradiation
It exposure of a gem to an artificial source of radiation to change its colour. This process often combined with a secondary step of heating also known as a “combination treatment”, to achieve certain colours like green, blue, brown, yellow, black and etc. Sometimes this process will be followed by annealing. Irradiated diamonds are sensitive to heat and jewellery repair procedures, recutting, and repolishing can change their colours.
- Annealing
This is a controlled heating and cooling process which is often used after irradiation to change a diamond’s colour to brown, orange, or yellow. It has been reported to produce pink, red, and purple colours as well. When annealing is used by itself, it can change the colour in a series – generally blue to green to brown to yellow. The treatment is stopped when the desired colour is reached. If heat is later applied to an annealed diamond during routine jewellery repairs, it can drastically alter its colour.
- High Pressure, High Temperature (HPHT)
Not only diamonds are created by this method (about the diamond creation will be in 4-th article), but also to improve diamond’s colour. Interesting that for HPHT treatment are used the same machines as those used to grow diamonds. The HPHT process can turn some brownish diamonds to colourless or transform brownish stones into other colours like yellow, greenish yellow or green; also makes pink, blue, and orange-yellow diamonds. HPHT is considered a permanent process. Sometimes it is followed with annealing and irradiation which can yield pink-to-red to purple colours. The method is laboratory detected only.
- Coatings
Silica coatings can be applied to polished colourless or near-colourless diamonds to produce a variety of natural-looking fancy colours, including pinks, oranges, yellows, blues, and purples. Coating enhances by masking an undesirable body colour with an ultra-thin layer of chemicals or plastics. Another form of coating involves applying a thin film of laboratory-grown diamond to the surface of a diamond simulant, giving it certain characteristics of a real diamond. It is fairly durable but not permanent. Coated diamonds can be damaged by heat and chemicals (acid etc.) during jewellery repairs and polishing. They can also be scratched.
Treatments for Clarity enhancing
- Fracture filling
Infusing molten leaded glass-like substance into a diamond’s fractures (“feathers”) – is the most common treatment used to enhance clarity. Fracture filling of surface reaching breaks can effectively disguise these features. It might also benefit a customer or jeweller who accidentally cracks a diamond (yes, it is possible, see “Diamond Hardness”). The treatment can last for years with proper care, but the filling can be damaged during common jewellery repairs, or if subjected to repeated cleanings with steam, acid or ultrasonics. If the filler melts and leaks out, there is a possibility that it can be retreated. If the filler turns dark, it cannot be made colourless again. Fracture filling can make a diamond look more attractive, but also slightly lower its colour.
- Laser drilling
Diamond manufacturers can employ lasers to remove or lighten a dark-appearing inclusion by drilling a tiny hole to the site of the inclusion. The laser may cause the inclusion to vaporize or the treater may apply bleach or acid to lighten the inclusion further. Laser drilling can make included diamonds more marketable, but the laser drill hole is considered a clarity characteristic. The drill-hole can fill with foreign material and become more visible. Laser drilling is considered a permanent treatment as the drill hole cannot be removed. Sometimes after drilling, the diamond may be fracture filled. (http://4cs.gia.edu/en-us/blog/diamond-treatments-mean/ ; http://4cs.gia.edu/en-us/diamond-treatment/)
These are only few methods and there will be more to come, so there is no point of mentioning all of them as well as the use of advanced technologies to treat diamonds makes detection more difficult, and requires the use of sophisticated instruments found only in the most well-equipped laboratories. That why it is so important for you as potential customer to consult with professional to know what you are buying. You have all the power in your hands.
Diamond Jewellery Cleaning
Diamonds are among the hardest natural minerals on Earth, yet they require special care to keep them shining and looking their absolute best. Dirt won’t break or chip your diamond, but it will dull its appearance, in fact a stone’s sparkle can be lost by the mere touch of a finger, which can cause dirt to collect on the diamond.
The best way to keep your diamond looking great: clean your diamond regularly. You have several cleaning options:
- By yourself
Using a lint-free cloth and/or washing it using warm water with soap or home chemicals. A simple plan to keep your diamond jewelry looking beautiful is to soak each diamond in an ammonia-based household cleaner (such as window cleaner) overnight, once a week. The next morning, remove the diamond from the cleaner and brush it with a soft, clean toothbrush (a new brush reserved exclusively for cleaning your diamond) to remove any leftover dirt. Take extra care to brush the back of the diamond, because this area tends to collect a lot of oil and dirt. Be gentle – you don’t want to loosen any stones, especially if the setting is fragile or older as in estate jewelry. Also, try to not clean your jewelry too close to an open drain in the sink. If you are cleaning by a sink, be sure there is something to prevent your jewelry from falling down the drain. N.B. Don’t use ammonia-based household cleaner if the diamond has been treated with a non-permanent substance like a coating.
Keeping your diamond clean is a good step in protecting your diamond. While a home method is perfectly acceptable, you should consider having your diamond cleaned periodically by a professionally trained jeweler.
- By professional jeweler
Using ultrasonic cleaner. This machine sends low frequency wavelengths through a liquid solution to remove the dirt and buildup on your jewelry. It is especially helpful for removing dirt in hard-to-reach places like beneath diamonds. This method is safe only for untreated diamonds; however, treated diamonds can be damaged. That is why first note what kind of diamond you have and only then give it to the professional jeweler to clean it.
Using a steam cleaner. A steam cleaner will use high-pressure steam to remove dirt and build-up. A steam cleaner has a water reservoir that’s heated to produce a high-pressure steam that’s around 50 up to 55 psi. As previous method, steam cleaners are chemical free, what makes your jewelry safe from any damages possible, that is why these professional methods are the best solutions. But again, know what kind of jewellery you have and give this information to your jeweler.
While the instructions above will keep your diamond sparkling, there are a few things to be aware of. Fragile settings and older estate jewelry may not respond well to the scrubbing of a toothbrush, so use a soft touch. If you haven’t had your ring setting inspected, be aware that diamonds can work loose from their settings if the settings aren’t secure You’ll want to find a safe place to clean your diamond. If it can be avoided, do not clean your jewelry in or near the sink. If a sink is the only option for cleaning your jewelry, be sure to cover the sink drain so that you can protect your jewelry from going down the drain. Also, use a rubber sink mat when possible to prevent jewelry from breaking or chipping if dropped. Finally, avoid 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 types of products can erode some of the metals often used in diamond settings, and they may loosen prongs or even dissolve the metal completely.
If you follow the check-up advice above, your diamond jewellery will retain its sparkle for a lifetime.