Common Diamond Treatments

Diamond treatments and how they affect you as a buyer:

While shopping for a diamond, you may have come across the terms “diamond treatment” or “treated diamond”  or perhaps something along the lines of “enhanced diamond”, but what does that really mean to you as a consumer?

Color-treated diamonds are common and are significantly less expensive than their natural counterparts.

Color-treated diamonds are significantly less expensive than naturally colored diamonds.

It is clear from the wording that something was done to the diamond, but how does it affect you and your purchase? Not only today, but in the future!

A relatively small percentage of gem-quality diamonds on the market are treated and they are usually treated to improve a diamond’s clarity, or its color, and sometimes both.

Although they can improve a diamond’s overall appearance, the treatment may not always be permanent, and therefore could become a problem down the road.

Here’s a quick overview of some of the more common treatments seen today:

CLARITY BASED:

Laser drilling:

Some diamond manufacturers use lasers to remove dark inclusions within the diamond by drilling to the actual site of the inclusions within the diamond.

The laser may cause the inclusion to vaporize, or bleach is used to lighten the color of the inclusion even more.

Laser drilled hole in a natural polished diamond looking like thin white channel

Laser drilled hole in a natural polished diamond looking like thin white channel.

Laser drilling might make the diamond more marketable, but the laser drill hole is considered a clarity characteristic and thus will affect the diamond`s clarity grade, and subsequently it’s value.

Laser drilling is considered a permanent, and therefore, industry-accepted treatment as the drill hole cannot be removed.

Fracture Filling:

Infusing molten leaded glass-like substance into a diamond’s fractures – is the most common diamond treatment used to enhance clarity. Fracture filling of surface reaching breaks can effectively disguise these features.

foreign substance is infused into cracks in the stone to improve its naked-eye visual clarity. Because the filling is not permanent, GIA and most other gem labs will not grade fracture-filled stones.

Molten leaded glass is infused into cracks in the stone to improve its naked-eye visual clarity. Because the filling is not permanent, GIA and most other gem labs will not grade these stones.

The treatment can last for years with proper care, but the filling can be damaged during common jewelry repairs, or if subjected to repeated cleanings with steam, acid or ultra-sonic cleaners.

Because the treatment is not permanent, many grading laboratories, including the Gemological Institute of America, will not provide grading reports for diamonds that have been subjected to this particular type of treatment!

COLOR BASED:

Irradiation:

Irradiation can produce green, blue, brown, yellow, black and other colors. Sometimes this process will be followed by annealing. Irradiated diamonds are sensitive to heat and jewelry repair procedures, recutting, and repolishing can change their colors.

Irradiated diamonds are genuine diamonds that exhibit an intense color change such as blue or pink or green etc., after being exposed to a strong radiation treatment.

Irradiated diamonds are genuine diamonds that exhibit an intense color change such as blue or pink or green etc., after being exposed to a strong radiation treatment.

Annealing:

This is a controlled heating and cooling process which is often used after irradiation to change a diamond’s color to brown, orange, or yellow. The treatment is stopped when the desired color is reached.

If heat is later applied to an annealed diamond during routine jewelry repairs, it can drastically alter its color, and the treatment is not considered permanent.

High Pressure, High Temperature (HPHT):

High Pressure, High Temperature (HPHT): essentially uses the same process as that used for manufacturing synthetic diamonds.

The process can turn some brownish diamonds colorless or transform these brownish stones into other colors like yellow, greenish yellow or green.

Identifying HPHT diamonds involves specialized laboratory techniques such as spectroscopy and photo-luminescence.

The improvement in colour can be dramatic. Brown diamonds of N to O colour, and even Fancy Light brown diamonds, can attain D to H grades after HPHT.

The improvement in colour can be dramatic. Brown diamonds of N to O colour, and even Fancy Light brown diamonds, can attain D to H color-grades after HPHT.

HPHT is considered a permanent process, and is an industry accepted enhancement. The Gemological Institute of America (GIA) has been accepting HPHT processed diamonds for full grading reports, since 1999.

Coatings:

Silica coatings can be applied to polished colorless or near-colorless diamonds to produce a variety of natural-looking fancy colors, including pinks, oranges, yellows, blues, and purples.

The intense pink color of these diamonds is the result of a surface coating. This is not considered permanent nor standard industry practice, and therefore, should always be disclosed! (GIA)

The intense pink color of these diamonds is the result of a surface coating. This is not considered permanent nor standard industry practice, and therefore, should always be disclosed! (GIA)

The coating is fairly durable but is definitely not permanent. Coated diamonds can be damaged by heat and chemicals during jewelry repairs and polishing.

They can also be scratched. This means detection and disclosure are vital when handling coated colour-treated diamonds.

 DISCLOSURE:

It is important to understand that as a consumer any of the above-mentioned treatments, except laser-drilling and HPHT treatments, should always be disclosed to you before you make your purchase! Unfortunately, this is not always the case….

Therefore, as a consumer, you should always insist on buying a certified diamond that has been professionally graded by a reputable grading laboratory, such as the Gemological Institute of America (GIA).

Always insist on a certified diamond from a reputable grading laboratory.

Always insist on a certified diamond from a reputable grading laboratory.

These labs use sophisticated instruments to detect any of the above mentioned treatments, and if they are present will be clearly identified in the grading-report that comes with your diamond.

Most reputable jewellers will work closely with you during the purchasing process, and will clearly explain to you everything outlined in the report that comes with your diamond.

At the end of the day, it pays to be vigilant, so always insist on a grading report, and most of all, be sure to ask your jeweller to explain anything you don’t understand before you commit to the purchase!

We hope this article has given you a bit more of a background on the more common diamond treatments in today’s market-place, but should you have any additional questions about this or any other jewellery related topics, you can always: “Ask Our Jeweller”

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This article was compiled from my personal knowledge as a gemologist, as well as numerous online sources, individuals and textbooks. If you have something to add to this article that you feel would be of benefit to others, please, do not hesitate to contact us.

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