Diamonds
Definition
A diamond is precious stone consisting of a clear and colourless crystalline form of pure carbon, the hardest naturally occurring substance.The price for a diamond is determined by the colour,carat.clarity and cut.
Carat
Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams.
Each carat can be subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place. A jeweler may describe the weight of a diamond below one carat by its ‘points’ alone. For instance, the jeweler may refer to a diamond that weighs 0.25 carats as a ‘twenty-five pointer.’ Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as ‘one point oh eight carats.’
Colour
The colorless or white diamond color are the most common, whilst some tinted stones, colored diamonds, are extremely rare and valuable. The shades of Diamond Color include yellow, blue, black, pink, red, orange, green and brown. Diamond Color is determined by the impurities or structural defects that cause the coloration. Pure or nearly pure diamonds are transparent and colorless – referred to as a white diamond color.
A diamond’s cut grade is an objective measure of a diamond’s light performance, or, what we generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out of the top of the diamond . If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.
Ideal cut: Our most brilliant cut, representing roughly the top 1% of diamond quality based on cut. The highest grades of polish and symmetry allow it to reflect even more light than the standard ideal cut.
- Ideal cut: Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut.
- Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price.
- Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut.
- Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.
- Poor cut: Diamonds that are generally so deep and narrow or shallow and wide that they lose most of the light out the sides and bottom. Blue Nile does not carry diamonds with cut grades of poor.
Clarity
Clarity has a big role in determining the value of a stone.Just like us, diamond have “birthmarks.” Theirs are known as inclusions or blemishes, depending on whether the marks are internal or external.
The GIA Clarity Chart from the International Diamond Grading System™ uses eleven possible measures depending on the visibility of inclusions and blemishes. Most diamonds are graded within the VS or SI categories.
FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3
Details below are quoted from the GIA’s official website http://www.gia.edu
Flawless (FL)
No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF)
No inclusions and only minor blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2)
Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2)
Inclusions are clearly visible under 10× magnification but can be characterized as minor
Slightly Included (SI1 and SI2)
Inclusions are noticeable to a skilled grader using 10× magnification
Slightly Included (SI1 and SI2)
Inclusions are noticeable to a skilled grader using 10× magnification
Imperfect (I1, I2, and I3)
Inclusions are obvious under 10× magnification and may affect transparency and brilliance.
Consider the examples in these pictures:
