QUOTE
Plenty of girls/guys do not know much about diamond, why some are expensive why some are cheap, why tiffany diamond cost twice as much as poh kong? am I conned? am I conned by my bf?
I was involve in Diamond wholesale since 2000, I can share quite a few things even tho am a bit rusty but I think should be reliable.
poll ends tomoro 11am, if yes then we shall create a thread all about diamonds, BTW voting the no3 option is consider spoiled vote
Every girl looks forward to the day when they are surprise by the love of their life with a tiny red velvet box, opened and you will be mesmerized by the glittering play of fire, luster from the most romantic stones set in a ring of precious metal. For this ring is the beginning of the sacred matrimony, the promised of commitment, and the day to be remember for as long as you live.
However the guy goes through a ton of confusion, as most guy knows near zero of the complication of buying a diamond, a diamond is near as complicated as the girl they want to live with. I hope this thread will be helpful and give you better understanding.
Diamonds are complicated with too many criteria to scrutinize, just a single pinhead inclusion viewable only with an 10X magnifier could plunge its value from a few hundred to thousands. This thread purpose is to help prospect diamond customer to better understand the value and diamond itself before buying that precious stone for your proposal ring.
I was in the gemstone wholesale industry since 2000, but had stopped trading diamonds since 2004 and dealt with other custume jewellerys, I'll share with you as much as I know and tho a bit rusty, since gemstone industry progress pretty fast with all kind of synthetic and fake duplicating technology coming up every year. However most of the knowledge is still pretty useful.
Diamonds are graded with a 10X magnifier/loop, you can see more inclusion (inperfection/foreign particle) with a greater magnifier eg 20X or a microscope but that wont be included in the grading report. So whatever seen with a 10X loop is all that matters to the value of your stone.
There is the famous 4Cs to value, mainly Cut, clarity, color and carat.
Cut
Cut is the most important criteria, which unfortunately the certificate tells us very little about, there is still too much space and loopholes to play around. Cut is also the make or break of a diamond. A 58 facet and 90 over facet cut can have a huge difference in fire and lustre. Hearts and Arrow are pattern symmetry but there may lose fire play to traditional cut. Also remember not all hearts and Arrow are equal, Dont think just because your diamond possessed the H&A and you've the best cut diamonds, it only means your diamond are cut with a hearts and arrow pattern thats all.
Cut can also determine the visual size of your diamond, a 1 cts stone may look bigger like a 1.3 cts stone if the table is cut slight larger in proportion, but there is always a penalty somewhere.
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Proportions and cut determine the brilliance of a diamond. In order to maximize this brilliance, the diamond cutter must place each of the diamond's facets, which act as light-dispersing mirrors, in exact geometric relation to one another. On a classic Round Brilliant cut diamond, fifty eight (!) facets must be precisely aligned. Few diamonds are cut to exacting standards since diamond cutters try to maximize their returns on the raw material by leaving the stone as large as possible with minimum waste. As a result, the proportions, symmetry and perfection of the cut and shape may be delegated to play a secondary role. The result is usually a compromise between profit (e.g., size) and beauty (perfection of cut, proportions and shape).
The most important criteria of the Cut is the ratio of the depth to its diameter ( i.e. Depth/Diameter). In order for the diamond to be considered within the "Ideal" tolerance bracket the ratio should be between 58/100 and 62/100 or, "58%" and "62%" respectively (see illustration). The measurements are taken in millimeters through the use of a Leveridge Gauge or Micrometer "Table" diameter percentage ( see illustrations for definitions of the names of the different diamond facets ) ; "Crown" angles and "Girdle" thickness & symmetry are also important. Each of these proportion criteria have tolerance ranges which, however, are less crucial when violated than deviation from the above Depth/Diameter ratio ( "Percentage").
Marcel Tolkowsky is credited with calculating in 1919 the ideal proportions and facet angles that create maximum brilliance and fire. Unfortunately the "ideal cut" results in smaller weight yield from the rough diamond crystal and is rarely practiced. Most cutters today slightly compromise Tolkowsky's "ideal cut" but still create impressive results.
When the diamond is well proportioned the path of a beam of light is returned directly back to the eye instead of escaping through the bottom or sides of the cut diamond, as a result the diamond will be more lively and brilliant.
The Gemological Institute of America (GIA) scale for the diamond's Cut (proportions) is described using the terms "Excellent", "Very Good", "Good", "Fair", and "Poor" ("Recut").
Clarity
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Clarity refers to the inclusions and blemishes in the crystal. Gemologists refer to these blemishes, rather, as identifying characteristics avoiding any negative associations and connotations. One must remember that a diamond is a natural substance and any inclusion or pattern of inclusions can be considered as the diamonds unique natural characteristic and "fingerprint". They can also help identify the diamond making your diamond as unique as a snowflake, since no two are exactly alike.
Diamonds are graded for clarity according to the number, size, location and type of inclusion. Obviously, less numerous and smaller inclusions that are less centrally located are more desirable than the opposite. Examples of the type of internal inclusions include: "pinpoints", included crystals that are transparent, opaque or carbon . Groups of pinpoints are called "clouds" and fractures are called "feathers". External blemishes include polishing lines, grain lines ( mineral growth twinning planes), scratches,chips, nicks and naturals (part of the rough diamonds original surface or "skin").
Diamond Clarity Grading Terminology :
As the value of a diamond is determined, partially, by its "purity" or "clarity", standards for measuring the diamond's clarity have been put into place . The clearer the diamond is the rarer and therefore, the more valuable it is . The following terminology is used by the industry. The letter abbreviations are sometimes confusing to the novice but still are of high importance .
The G.I.A Clarity Scale:
F
Flawless diamonds in this category are free from internal and external imperfections when examined by skilled professionals under natural or artificial light with a 10X loupe corrected for chromatic and spherical aberration or with a 10X binocular microscope equipped with dark field illumination. ( The following conditions still qualify a diamond as flawless: an extra facet located on the pavilion which cannot be seen from the face-up position; a natural that does not extend beyond the maximum width of the girdle or break the symmetry of the girdle outline and is not seen from the face-up position )
IF
Internally Flawless diamonds in this category are free from all internal imperfections (inclusions) but do possess minor surface blemishes. Normally these diamonds may be made flawless by minor repolishing with the exception of surface grain lines.
VVS1 and VVS2
(Very Very Slightly Inclusions, level 1 or 2)
These grades contain minute inclusions so small or insignificant that they are difficult to locate under 10X loop. When these inclusions are very difficult to locate visible only from the pavilion side or tiny enough to be easily removed by repolishing-the first VVS grade applies. Pinpoints, faint clouds, tiny feathers or bruises characterize the VVS grades.
VS1 and VS2
(Very Slightly Inclusion, level 1 or 2)
These grades imply minor inclusions of a size, number and location that stand between those somewhat difficult to observe and those somewhat easier to observe under 10X loop. Small included crystals, small feathers, distinct clouds characterize the VS grades.
SI1 and SI2
(Slightly Inclusions levels 1,2)
These grades contain noticeable inclusions which are easily visible under 10X loop. Normally these inclusions will be centrally located and noticed immediately when the diamond is examined. diamonds in these grades (particularly the SI2 grade) may disclose inclusions to the unaided eye when placed table down on a white background, but not when viewed face-up.
I1, I2 and I3
(observable Inclusions levels 1,2 & 3)
The "Imperfect Categories" contain obvious inclusions when viewed under 10X loop and are visible to the unaided eye in the face-up position. The grades vary from diamonds with inclusions that are difficult to locate by the unaided eye to those with severe inclusions that are easily noticeable.
Though a diamond is said to be "flawless" if no inclusions (internal or external) can be seen under 10 power magnification (triplet loupe or binocular microscope) truly flawless diamonds are extremely rare.
The VS1 category is the cut-off point for what is considered to be a fine clarity grade since the inclusions characteristic of this grade are extremely small and difficult to see at 10X magnification. To the left of the scale from the VS1 grade the differences between each clarity grade are significantly smaller than clarity grades to the right of the VS1 category, where the tolerances for each grade are larger. SI grades are still considered to be very good to good, since their inclusions are not eye visible, especially
when examined under normal lighting conditions. Under gemological laboratory conditions where daylight is used the inclusions in the SI2 grade are eye visible when viewed through the back of the diamond (known as the "Pavilion View"). SI grades are considered good choices especially when combined with good color and cut since the cost due to the clarity is usually within popular price ranges and budgets.
Color
A tip for the not millionaires, buy F color diamond, it is very difficult for an untrained eye to differentiate between a D and F colored stone, save the rest of your money for the other 3 Cs.
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All diamonds possess trace amounts of yellow or brown – the most valuable diamonds tend to be the colourless diamonds. However, very deeply coloured diamonds, such as a brilliant canary yellow diamond, can actually cost more than a colourless stone. These ‘fancy diamonds’ (also called Z+ diamonds) are even rarer than their colourless counterparts, and can also be found in blue, green, black, red and pink. The most famous fancy diamond is the deep yellow Tiffany diamond. Another famous gem is the Millennium diamond, the world’s largest 'D colour' diamond for its virtual flawlessness.
The chart below explains the grading of diamond colours from D to Z. Colourless diamonds are graded D and are very rare. The colour of a diamond can affect the setting in engagement rings. White colours are often set in white gold or platinum while the warmer tones are often set yellow gold.
Carat
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1 carat = 100 points = 200 milligrams (one fifth of a gram)The cut and setting can often make a diamond look bigger than its carat weight so examine all 4 standard measurements before buying. Large diamonds are quite rare and naturally, prices increase significantly with the carat weight. If you want a high carat diamond, often the case when buying an engagement ring, consider a slight downgrade in size.
If you're planning to buy a 0.30 or bigger stone, I would always go for a stone with certificate, the famous industry standard are from
GIA (Gemological Institute of America)
AGS (American Gem Society)
These 2 cert are the popular traded diamond in Malaysia, however we also have our local gemology's Mr Chris Lam who would issue a Diamond grading report.
I always prefer an F color stones with a hint of florescent presents in the stones, slight florescent will make the stone look more colorless or whiter, and in certain sunny condition your stone may have a slight blue tint which I like very much.
You can learn how to read a diamond cert here
http://www.diamondring.com/forums/diamondt...al.php?learn=19When shopping for diamonds ...ASK the shop to show you the latest RAPAPORT, this is the industry pricing of diamond in USD. Rapaport are issued every fortnightly and the prices differs, how much discount you get will depend on your negotiating skill.
Spoiler part are taken from
http://www.esva.net/~jhilton/4c.html and
http://pages.ebay.co.uk/buy/guides/diamonds-buying-guide/ since I'm too lazy to type out these standard criteria
This post has been edited by moorish: Apr 24 2009, 12:54 PM