How Does Color Gem Grading Differ From Diamond Grading?
The 4 C’s of diamond are becoming more widespread, thanks to the rise of the online diamond consumer. When it comes to evaluating colour gemstones, however, there is a bit less certainty. De Beers has spent millions of pounds on advertising, and most customers are aware of the fundamental framework for determining the worth of white diamonds:
– Carat weight (weight)
– Make a cut (shape and proportions)
– The colour (colourlessness)
– Transparency (lack of inclusions)
Even a beginner customer may comprehend that the higher the carat weight, the better the cut, the cleaner the stone, and the ‘whiter’ the colour, the more the stone is worth using this framework. Furthermore, all of these features may be checked to the nth degree for even the most apprehensive of clients using 10x magnification (typical for diamonds).
Color gemstones and diamonds, on the other hand, are not sold using the same criteria as white diamonds. Color is the most strongly weighted factor, even if cut, clarity, and carat weight are still crucial. The more vivid the colour, the rarer and more precious the stone is in general.
The fundamentals are the same with rubies, sapphires, and emeralds, although they are more difficult to quantify. This isn’t to say that there aren’t any standards in place. On the contrary, there are a few fundamental criteria for determining colour gemstone quality.
What is the Best Way to Grade a Color Gemstone?
When grading gemstones, like with diamonds, the colour will always be at the top of the list. The regularity, attractiveness, and quality of the colour is fundamental predictor of quality and value in coloured stones.
Colour is rated based on tone strength, with a stronger tone attracting a greater price unless it becomes excessively dark, in which case the value is drastically reduced. The colour of a stone can vary dramatically depending on its origin, which has an impact on its value.
Instead of using cold descriptive language to describe the notion of colour in gems, use words like vibrant, fiery, deep, unique, warm, gemmy, and lively. Using these emotive phrases makes it much simpler to create an image in the customer’s head. It will assist them in visualising how it will seem in the setting in which they will be wearing it. Vibrant, Fiery, Deep, Unique, Warm, Exceptional, and Lively are all great personality qualities, and who wouldn’t want to acquire a stone or piece of jewellery that reflects their personality?
Carat
Larger stones are always thought to be more precious than smaller ones. To some extent, this is correct; nevertheless, if all other factors are in places, such as excellent colour, outstanding cut, and remarkable clarity, smaller stones might be more expensive than larger ones. In reality, the huge stone just described is referred to as “bluffy.” Meaning it appears to be much better than it is, and closer scrutiny reveals several problems.
Cut
In the same way that the intricacy of the cut affects the beauty and reflection of light of a ‘white’ diamond or coloured diamond, the intricacy of the cut does not impact the beauty and reflection of light of coloured gemstones. Coloured stones have their own natural “glow,” which is only accentuated by the stone’s cut quality and style. A simple cut can just as well as a complicated cut to highlight the good points of a colourful stone. Unlike diamonds, the amount of facets on a stone has no bearing on its value. In fact, it can occasionally distract from the stone’s potential brilliance.
Colored diamonds are impacted by cuts in the same manner as ‘white’ diamonds are, but the appearance of the stone is still the most significant element. Place the gemstone certificate on the table and examine the stone!
Clarity
The absence of inclusions in the stone is referred to as clarity. It’s worth mentioning that inclusions in coloured stones are quite frequent and only have a little impact on the price of a stone. Opaque stones, on the other hand, are far less expensive unless they are eye clean or loupe clean, which can command a much higher price.
Unless looking at very fine natural stones when the impurities (or lack thereof) make the difference between a lower and higher price, clarity is usually judged with the naked eye. While inclusions are virtually always present in emeralds, especially bigger stones, they do not devalue the stone. If inclusions are anticipated, then included stones become the standard, whereas clear stones are unusual and command a higher price.
When defining gemstone clarity, try to avoid using diamond jargon. Loupe Clean, Eye Clean, tiny inclusions, and included are the terms used in general. Keep in mind that this is usually subjective. Buyers are less flexible than sellers when it comes to this.
Disclosure of Treatments
Regardless of whether the gemstone is natural or treated, or synthetic, all information relevant to any enhancement technique performed on a natural gemstone must be reported when:
– the stone has been treated; or – the treatment is temporary and its effects fade over time (e.g. oil in emeralds); or – the treatment necessitates special care for the gemstone to maintain the benefit of the treatment (e.g. oil in emeralds); or – the treatment has a significant impact on the gemstone’s value (e.g. oil in emeralds); or – the treatment has a significant impact on (e.g. heat treatment in rubies and sapphires, or oil or resin in emeralds, or irradiation in diamonds).
Most gemstones, in general, are subjected to some form of treatment. I’d even go so far as to say that it’s usual for rubies, sapphires, and emeralds to have had some form of augmentation, which is OK as long as it’s revealed.
Rubies, Sapphires, and Emeralds are commonly treated.
Heating is the most frequent treatment for rubies and sapphires. Inclusions and colour impurities have been eliminated or decreased, and in some cases increased, by heating at a high temperature. Any additional heating, particularly on rubies, includes the introduction of a glass-like substance that melts at extremely high temperatures and fills any surface-level defects in the stone, making it more stable, brilliant, and clean.
Emeralds, on the whole, go through an oiling procedure. This is usually done using natural or synthetic oils and is used to seal any cracks in the surface (very common in emeralds). Natural oils can dry out with time, yet some consumers find them more acceptable than a permanent synthetic resin. Vacuum is used to introduce the oils and resins, which are effectively sucked into the cracks and fissures.
All artificially enhanced colour treatments must be declared!
Stones that have an excellent appearance but have not been treated in any way are exceedingly rare, accounting for less than 1% of total production, are incredibly valuable, and are usually accompanied by at least one certificate to substantiate this fact.
There should be no colour or purity improvements in natural colour diamonds. If there are any, they must be disclosed very away, since this will significantly diminish the diamond’s value.
Origin
The provenance of a gemstone can have a significant impact on its value. With the exception of pink Argyle diamonds, it is more essential in rubies, sapphires, and emeralds than in colour diamonds. The main reason why provenance has an impact on pricing is because each geographical place gives a stone its own distinct appearance. Burmese rubies and sapphires differ significantly from those found in Mozambique or Madagascar.
The origins of rubies are often divided into two geographical locations. Burma, Thailand, Vietnam, and Sri Lanka are all in Asia. Mozambique, Tanzania, and Madagascar are all in Africa. Burma is the most coveted country.
Sapphires have a similar origin storey to rubies, however the most valuable sapphires originate from Kashmir, which is now mainly depleted, followed by Burma, Sri Lanka, Madagascar, and other countries including Thailand, Australia, China, and even Montana (prized mostly by Americans).
The following are the primary sources of Emeralds: Colombia is more appealing. Gemfields has increased the popularity of Zambia. Afghanistan and Brazil supply the market with very tiny stones.
Mineral that should not exist on Earth discovered hidden in a deep-surface diamond
