If you speak about Diamonds you should know the basics - like the 4C's.
CaratDiamonds are sold by the carat (ct). This is a unit of weight. Don't confound it with the karat of Gold. By Gold means karat the purity.
One carat are 200 milligrams. This standard has been established in 1914 by the International Committee of Weights and Measures.
Gemstones of less than one carat, jewelers often refer to the weight in terms of points. A carat is divided into 100 points, with one point corresponding to .01 carat.
Although the analogy of pennies to the dollar suggests that one carat is always 100 points, or that one-half carat is always 50 points, that's not entirely true. Diamonds can't all be uniformly cut to such exact weights of 100 points, so the carat weight given is an approximation of the actual weight of the gemstone.
The clarity term to a gemstone's purity. The Clarity is rate by viewing the diamond under 10x magnification. Virtually all diamonds contain tiny natural birthmarks that are present to varying degrees. After all, nature isn't perfect at all. So every gemstone is unique and has his own "personality" in form of tiny natural enclave.
Nearly all diamonds, also diamonds of the highest quality, have some enclaves. , which fall into these categories:
A dark spot from a trapped bit of mineral
Open cavities interrupting the diamond surface that were a part of the original diamond crystal
Internal cracks or fractures caused by either internal or external stress during the diamond's formation.
Clarity graduation system
There are several grading systems used in the industry, the most recognized and common used system is developed by the Gemological Institute of America (GIA).
|FL||Flawless. Shows no inclusions or blemishes of any sort under 10x magnification when examined by an experienced grader. Extremely rare.|
|IF||Internally Flawless. Has no inclusions when examined by an experienced grader using 10x magnification. Very rare.|
|VVS1, VVS2||Very, Very Slightly Included. Contains minute inclusions that are difficult even for experienced graders to see under 10x magnification.|
|VS1, VS2||Very Slightly Included. Contains minor inclusions ranging from difficult to somewhat easy to see for an experienced grader when examined under 10x magnification.|
|SI1, SI2||Slightly Included. Contains inclusions that are easy to very easy to see for an experienced grader under 10x magnification. Some inclusions may be visible to the unaided eye.|
|I1||Included. Contains obvious inclusions visible to an experienced grader under 10X magnification; can be visible without magnification.|
|I2, I3||Included. Contains obvious inclusions. Visible without magnification.|
ColorThe quality of color refers to a diamond's body color, not the rainbow surface of reflected light.
less color is more valuable
When buying a diamond, it is the absence of color that makes one diamond more precious than another. The whiter or more colorless the diamond, the more rare, and the higher is the price. The exception is "fancy" colored diamonds, which can occur in shades of blue, red, yellow, pink, brown and green. Some of these are exceptionally rare and considered collector's items.
Measurement of colour
Color is graded by the Gemological Institute of America (GIA) with letters ranging from D (completely colorless) to Z (light yellow).
|GIA Color Rankings||Description|
|D, E, F||Colorless (like clear water)|
|G, H, I, J||Near Colorless|
|K, L, M||Faint Yellow|
|N, O, P, Q, R||Very Light Yellow|
|S, T, U, V, W, X, Y, Z||Light Yellow|
CutThe cut is extraordinarily important because it has the greatest single influence on the diamond's brilliance. And the sparkle is what that women adore to diamonds.
So pay special attention to cut when evaluating diamonds.
A laboratory grade is only part of the story, because diamonds with the same grade can have very different amounts of sparkle, depending on how each diamond is cut and where the inclusions are located inside the diamond.
|Crown||The part of the diamond above the girdle|
|Table||The large facet that caps the crown of a gemstone|
|Girdle||The outer edge of the diamond, usually the portion that is grasped by the setting. It is the dividing line between the crown and the pavilion.|
|Pavilion||The part of the diamond below the girdle.|
|Culet||The small facet parallel to the girdle, at the bottom of the gemstone.|
Shapes of Diamonds
At the same time, he has to find the optimal balance between yielding the most diamond weight and creating the best proportioned cut. One reason why higher grades of cut are so much more costly is because more diamond was sacrificed to create them. That's also why a well proportioned one-carat diamond may be worth twice as much as a poorly proportioned larger diamond that lacks fire and brilliance.
For centuries, diamond cutting experts have pondered what combination of proportions creates the optimal balance of brilliance, scintillation and dispersion.
The 58-facet model developed in 1919 by master gem cutter and mathematician Marcel Tolkowsky has provided a foundation for today's most widely accepted proportions. However, while Tolkowsky's model dictated precise proportions for table diameter, crown height, pavilion depth, crown angle and pavilion angle, many grading labs and diamond sellers today offer a more liberal interpretation. The market itself dictates a wider range of acceptable proportions.
In fact, the Gemological Institute of America (GIA), the world's leading gemological authority, actually advises against using the term "ideal" cut. Why? Because the GIA has demonstrated that literally thousands of variations on these proportions can maximize the different optical characteristics displayed by a diamond. As long as the diamond's proportions fall within the acceptable range of tolerances, you can be assured of buying a gemstone that is well made.
The way a gemstone is cut can affect its appearance in other ways. If the diamond has a deep cut, it actually looks smaller than another diamond of the same weight that is cut well. Likewise, a diamond that has a spread cut (cut shallow) will appear larger than another diamond of the same weight that is cut well. A diamond that is cut either too deep or too spread is typically undesirable.