The Sunday Mail
Maison Phiri
The cleanest diamond is referred to as flawless and must not have any imperfections that block light as it enters the diamond. Some laboratories go to the extent of using microscope analysis to determine a flawless diamond.
If a diamond has no imperfections, then the light path as it enters and exits a diamond is not disturbed. The stone will split the white light into rainbow colours and ‘beauty’ will become a short word to describe the phenomenon.
Diamond price is also controlled by the weight of each stone. Basically, the bigger the stone, the better the price. Huge stones are auctioned separately. Some stones are as small as sugar grains and you may probably find them glittering in expensive watches. More often than not, smaller stones have better clarity than larger stones.
The impact of clarity on price
The carat is the basic measuring unit for diamond weight and it relates to other weight measures as follows:
1 gram(g)= 5 carats(ct)
1kilogram(kg)=1000grammes(g) = 5000carats(ct)
The price indexes are graded in carat weight ranges and one thing to note is the price jump on all indexes from 0.99 carat which is in one range and one carat which happens to be in another range. There is a serious hike in price where there is not much difference in weight.
This is because the market recognizes a one carat solitaire more than a point nine. To this end, diamond cutters try to maintain weight above the one carat band where possible to enjoy the price increase and may actually sacrifice leaving in a few inclusions.
Another interesting point is the effect of single stone weighing more than 10 carats. All these stones are regarded as special stones and are sold separately when they have fair clarity. An interesting example is the recent discovery of a white potentially flawless diamond weighing 1109ct (approximately 222.2g) in the Botswana Karowe mine.
It sold for a value of USD53 million. Perhaps an important point to note is that conventionally, diamonds are priced in USD/ct. In this case if we do the math: $53 000 000/1109ct= $47 790.80/ct. That is the approximate price per carat that was offered for the diamond. A medium density house in Harare is worth one carat of that stone if you would like to extend your imagination.
However, please note that there are two Cs at play here – Carat and Clarity. The Karowe mine diamond is a potential flawless, and it is huge. The price would be revised downwards if the carat weight was less, or if the clarity was poor. A great decrease in price would occur if both clarity and carat were decreased. So, special stones which have better clarity sell for a fortune.
Perhaps another point to note on carat weight is that the price of two 0.50ct diamonds is less than that of one ct single diamond, all other Cs being the same.
This can be a rule of thumb. However, splitting diamonds has a catch where a rough stone can be split, separating inclusions from the final cut piece. For example if in an I1 rough diamond inclusions are on the left side of the stone and the right side is clear, it is better to split the stone and have a right side clear stone (SI1) and a left side poor stone (I3). This is a trick used by markers when cutting diamonds.
Another trick on carat is market preference. All solitaire rings with one carat stones are most sought after.
Most rings with two or three carats are usually never talked about until the stone is about five carats and above. I also understand that while the Asian markets are particular on clarity, the Western market is usually enticed more by the carat weight. It is a development that affects the aggression of your price negotiations.
Carat grading
There are no particular grading conventions on this and I have met a fair number of carat grading systems from various laboratories. However, carat grading depends on your market. If your market is particular about a certain size, you would rather grade it alone: Below is the author’s grading from experience, though not yet tried and tested:
There are sieves which are proportionate to these weights. This is because the diamond has a particular specific gravity of 3.52 almost uniformly distributed across the stone, so their volume is proportionate to their weight. Actually, gemologists can measure dimensions of a cut stone and weight can be determined using specific formulas.
This is an insight into carat; the bigger the diamond, the better. But carat is best combined with favourable clarity. A boart diamond weighing 50 carats may not sell for much. As a matter of fact, the price for a two carat flawless may be 1000 times more.
Maison Phiri (MBA, BSc, I.G.I -G.G,D.G,CSTG, HODTS) writes in his own capacity. Feedback: [email protected]
