How Pearls are graded
by Bina Shaji Kurup
A good pearl has several qualities and based on these qualities pearls are graded. There are two systems of grading pearls, which are accepted worldwide. One system is the
'Tahitian' system developed by the Polynesian government. This system is used to grade Black Tahiti pearls and other Saltwater pearls like the South Sea pearls. The other is the
'AAA-A' system, which is used to grade cultured Freshwater pearls.
The Tahitian System adopted mainly to grade Saltwater pearls grades pearls on a scale of "A" to "D". "A" signifies pearls of the highest quality and "D" are the lowest quality pearls which can be used to make jewellery. Any pearl lower than "D" grade is not used to make jewellery and is not exported out of the country. Lower than "D" grade pearls are used to make pearl powder and are sold only in Tahiti. The Tahitian system of grading pearls works as follows:
"A" quality pearls have a brilliant luster, reflecting images and colors clearly. They will have a clear surface with only 10% blemishes or flaws on the surface. These flaws are usually not visible since the hole is drilled over these flaws. Mainly these pearls are round in shape and their color is deep with overtones of Pink, Peacock Blue, Gold etc. These pearls are round in shape with a thick nacre coating, which is evident in the luster of the pearl. The pearls belonging to grade "A" are large pearls - more than 14mm in size. Grade "A" pearls are rare which makes them the most expensive pearls.
"B" quality pearls have a good luster and approximately one-third of the surface is flawed lightly. Their shape is round or semi-round and the flaws are often invisible from a distance and show up only on closer examination of the pearls. These pearls are between 12mm to 14mm in size with overtones of Gray, Pink, Gold etc.
"C" quality pearls are lustrous and pearls having less than 60% minor imperfections come under this category. These pearls are normally semi-round and have a variation of more than 5% in their diameter. Although there is a difference between the "B" and "C" grade of pearls, an untrained eye cannot really pinpoint the difference. The size or luster may vary and the shape will not be as round as "B" grade pearls. The pearls in this category are smaller and their color may not be as pronounced as the "B" grade pearls.
"D" quality is accorded to pearls if they have flaws like deep dents or cracks on the surface. Even pearls with high luster are graded D if more than two thirds of the surface is flawed.
Pearls below "D" quality or with flaws covering more than 65% of their surface are not used for making jewellery. To understand the differences in luster and surface of the pearl, try comparing pearls of different grades, it is possible to get a better understanding of how pearls are graded!
Black Tahitian pearls are renowned the world over and their color makes them unique. The beauty of these pearls is in their overtones. A plain black pearl costs much less than a similar pearl, which has overtones of Green, Pink, Gold Purple etc. (but brown shades are not considered to be a good buy) The exception to this rule is the large size pearls - exceeding 18mm, which are rare and are categorized as "A" grade irrespective of their color. Pearls with a mix of more than two colors are considered to be of a higher quality and command a higher price. Multicolor strands are famous in Tahiti and are absolutely eye-catching.
The other system for grading pearls is the "AAA -A" system. Used mainly for grading freshwater and Akoya pearls, sometimes even saltwater pearls are graded under this system. In this classification, the pearls are graded as being "AAA" (the highest grade), "AA" being medium quality and "A" being accorded to pearls, which do not meet the requirements of either "AA" or "AAA" grades. As with the Tahitian system, the pearls are graded as per their size, shape, color, surface, nacre thickness and luster.
"AAA" grade pearls are the ones with the highest luster, least blemishes on the surface and have a rounder shape (although perfect spheres are unusual in Freshwater pearls). These pearls have a thick nacre coating and are normally white with Pink or Gray overtones. Pearl strands cannot be of a higher grade than "AAA" grade and are expensive. Necklaces are also rare in this grade and most pearls are sold as strands or as individual pieces or as rings and pendants. These grades of pearls are the largest in size exceeding 8mm (sizes of 10mm or more amongst freshwater pearls are very rare)
"AA" pearls have a good luster and their surface is slightly flawed but hidden by mounting or drilling the flawed area, whereby only the flawless surface is visible. Their shape may be less round than the "AAA" grade pearls but not of a semi-round shape or a baroque shape. Rolling a pearl along a straight surface determines its shape - a straight line signifies a round shape, a zig-zag line signifies the shape is semi-round and a semi- baroque shape will rotate on one side only. The semi-baroque shape is further divided into drop, button, pear and oval - all four shapes are nearly similar with small differences. "AA" grade pearls are found in shades of White, off-white or cream with pink, silver and green overtones. They are available in sizes of 5mm to 8mm and have medium nacre thickness.
"A" grade pearls are available in many shapes and their natural shapes gives them a look that is unique yet elegant. These pearls have a flawed surface of more than 25%, but it is not visible from a distance. These pearls make an economical buy and are available in a variety of designs, a spectrum of colors and shapes like Rice or Seed pearls, Oval or pear shaped, Button and Baroque shapes. These are normally smaller size pearls between 1mm to 4mm in size. The nacre coating in these pearls is not as thick as pearls of "AA" and "AAA" grade pearls. But in no way does the lack of luster or size or shape reduce the beauty of these pearls.
Pearl jewellery, especially Necklaces and Strands of pearls are made of several pearls and not all of them may meet the same classification, some may be of an "AA" quality whereas some maybe of "A" quality. Also mounting or drilling the pearls at the point of the blemish cleverly hides blemishes and a dishonest jeweler can pass of "A" grade pearls as "AA" pearls and sell them at a higher price. The Lustre of the pearl cannot be hidden and that would be the best test to determine whether a pearl necklace is of "A" grade or "AA" grade. It makes sense to check each pearl for luster and flaws before buying an expensive piece. If a strand of pearls is graded "AAA", most of the pearls, if not all, must be of "AAA" quality.
The main difference in both grading systems is that under the Tahitian system, pearls are graded only as A, B, C or D. Under the second system, it is possible for sellers to give grades, which are higher or lower than the specified grades like AA+ for pieces that do not meet the specifications but are in between two classifications. This gives the sellers a little more flexibility.
Some sellers may tell you that the pearls sold by them are of "AAAA" quality, which is better than the "AAA" grade and not usually accepted as a grading measure. In such a scenario, remember some rules about "AAAA" pearls. "AAA" and "AAAA" pearls are different mainly in terms of their shape. "AAAA" pearls are the perfectly rounded pearls, which are very rare - especially in Freshwater cultured pearls. Since their availability is limited, these pearls are mainly used to make solitaire pieces like pendants and rings. A necklace or strand of pearls in the "AAAA" grade is almost impossible to find. They have a flawless surface and are normally smaller in size.
Pearls are delicate gems measuring 2.5 to 4 on the MOHS scale. Even our tooth enamel can leave scratches on its beautiful surface. Always buys pearls with a thick coating of nacre - which will protect it from cracking (in case it falls), discoloration and age.
Store your pearls separately away from other jewellery and remember the golden rule of wearing jewellery - " always put it on last and remove it first". This means that only after applying make-up, dressing up, spraying on perfume etc and finishing every aspect of getting ready should you wear your jewellery to protect it against any chemicals contained in sprays or cosmetics. Similarly, remove your pearls first and keep them safely to ensure they do not get damaged. Pearls do not need to be washed; just a mild rub with a dry cloth will remove accumulated oils and dirt and restore their luster. At regular intervals, return your pearls to your jeweler for re-stringing. A little care will go a long way in making sure your pearls remain lustrous and elegant for a long time.
Always buy from a reputed jeweler whether you are buying it from a store or via the Internet. Investing in a good quality strand or necklace can be a joy for years and will never go out of fashion.