Thought of the day

I thank whatever gods may be / For my unconquerable soul. / I am the master of my fate / I am the captain of my soul. ~William Ernest Henley, Invictus

Government's promises are like the Ringgit, they depreciate with time.



Wednesday, May 21, 2008

Diamond is Forever

"Have you ever done any research on the internet about diamonds?" CM asked me out of the blue.
"Huh? No wor." scratching my head.
And so, CM gave me a 15 minutes crash course on it.
Basically, it's all down to the 4Cs: Color, Clarity, Cut and Carat.
Before we get to that, lets get ourselves familiarise with the anatomy of a round brilliant cut diamond, shall we?

In short, a round brilliant cut stone would have 3 main parts: The Crown, Girdle and Pavilion as shown below.



The Crown can be subdivided into few smaller parts such as the table, star facet, bezel facet and the upper girdle facet. Likewise for the Pavilion, it consists of the bezel facet, pavilion facet and the cullet.

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"Do you know that each diamond will have a grading report certified by certain international groups like the GIA (Gemological Institute of America)? It's something like a birth cert and is unique to each diamond." asked CM.
"Huh? No wor." scratch my head again.
~~*~~
Note that there are many international groups and labs out there such as the Scandinavian Diamond Nomenclature (Scan DN), International Gemological Institute (IGI), Accredited Gem Appraisers (AGA), Holloway Cut Adviser (HCA), American Gem Society (AGS)...etc. GIA is just one of them and since that most of the diamonds sold in Malaysia are certified by GIA, the following discussion on the 4Cs will be based on the GIA standards.
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Colour
  • Grading from D-Z
  • Grade D-F is considered colourless.
  • Grade G-L is nearly colourless.
  • The value of the stone decreases as you scale down from D to Z.

Clarity
  • There are 2 types of clarity characteristics: inclusions (enclosed within a diamond) and blemishes (confined to its surface).
  • These characteristics help gemologists to differentiate between natural diamonds from synthetics and simulants.
  • Inclusions and blemishes are unique to each stone, like human's fingerprints. Hence, these features also enable one to identify individual diamond.
  • There are 11 clarity grades ranging from Flawless to I3 as shown below:

  • Any inclusions/blemishes from grade IF till VS2 is invisible to the naked eye.
  • The value of the stone degrade as you scale down from F to I3.

Cut

  • The picture below presents the proportion of an ideal cut diamond.

  • The proportions will affect the complex relationship of the stone with light: how light strikes the surface, how much enters the diamond, and how, and in what form light returns to your eye.
  • The goal of the ideal cut, is to have light enter a diamond, disperse the light as it bounces from facet to facet, thereby producing the different prismatic colors and brilliance, finally returning as much light to the eye as possible.
  • The result is a display of three attributes:
  1. Brightness is the combination of all white light reflecting from the surface and interior of a diamond.
  2. Fire is the colored flashes that can be seen in a diamond.
  3. Scintillation describes the sparkle of light you see in a diamond, and the overall pattern of bright and dark areas when you look at a diamond face-up.

  • Sometimes the shape of the rough diamond makes it impractical to cut a stone closer to "ideal" proportions without losing significant weight.
  • A shallow cut makes the diamond appears larger as you have a larger table, but the pavilion will be shorter in order to retain the same carat weight. Vice versa for a deep cut.
  • A shallow/deep cut will produce less brilliant diamond due to light leakage.
  • Diamonds cut with precisely aligned and optimally proportioned facets will produce a fascinating pattern called the Hearts and Arrows (H&A) when viewed through a gemscope as shown below:

  • One can see 8 hearts from the pavilion view (bottom) and 8 arrows from the crown view (top) under the gemscope.

Carat Weight

  • One carat (ct) equals 1/5 of a gram in weight.
  • For diamonds under a carat, each carat is divided into 100 points – similar to pennies in a dollar. 0.75ct. = 75 points, ½ ct. = 50 points

I never knew that these dazzling little gems can be so sophisticated and I always thought that the sole purpose of their existence is just to bedazzle the women and to burn a big hole in men's pocket...

3 comments:

gnap said...

wah.. now talk abt diamond somemore! pfft!

David Chan said...

Is that a hint that you should look for a wedding diamond? Gosh!!! You!!! Better tell me early if you got good news!!!

Hahahaha!!!

Learning to be Gustav Graves huh... :-P

Gnu said...

gnap: it's just a stone, but after learning more about it, I am able to appreciate it better:p

david: hehehe...suspense...wanna be Danny Archer lar...more yau yeng!