<\/p>\n\n\n\n
While you will need a qualified gemmologist or (in the case of antiques) a trade expert to assess the quality of a diamond, understanding how it works puts you at an advantage when shopping around. <\/p>\n\n\n\n
Grading Modern Diamonds<\/h2>\n\n\n\n
Grading a diamond properly using the 4Cs requires that stone to be loose. In modern diamond-buying, this means either buying a stone before setting it into jewellery, or acquiring a GIA certificate along with the jewellery you buy.<\/p>\n\n\n\n
Clarity
<\/h3>\n\n\n\n
Diamond clarity refers to the absence of imperfections, known as (internal) \u2018inclusions\u2019 and (external) \u2018blemishes\u2019. No diamond is completely flawless, but assessing the nature and number of imperfections under a magnification loupe can tell us how \u2018perfect\u2019 it is. The higher the clarity, the better.
<\/p>\n\n\n\n
The GIA Diamond Clarity Scale has 6 categories, some of which are divided, creating a total of 11 specific grades which are used around the world, regardless of the language. They are as follows:<\/p>\n\n\n\n
- \n
- Flawless (FL)<\/strong> No inclusions and no blemishes visible under 10x magnification<\/li>\n\n\n\n
- Internally Flawless (IF)<\/strong> No inclusions visible under 10x magnification<\/li>\n\n\n\n
- Very, Very Slightly Included<\/strong> (VVS1<\/strong> and VVS2)<\/strong> Inclusions so slight they are difficult for a skilled grader to see under 10x magnification<\/li>\n\n\n\n
- Very Slightly Included (VS1<\/strong> and VS2)<\/strong> Inclusions are observed with effort under 10x magnification, but can be characterized as minor<\/li>\n\n\n\n
- Slightly Included (SI1<\/strong> and SI2)<\/strong> Inclusions are noticeable under 10x magnification<\/li>\n\n\n\n
- Included (I1<\/strong>, I2<\/strong>, and I3)<\/strong> Inclusions are obvious under 10x magnification which may affect transparency and brilliance<\/li>\n<\/ul>\n\n\n\n
GIA Clarity Diagram<\/figcaption><\/figure>\n\n\n\n Cut<\/h3>\n\n\n\n
Assessing the cut of a diamond is the most complex of the 4Cs, but the cut makes a huge impact on the beauty and value of a stone.<\/p>\n\n\n\n
While most people think of the cut as the shape<\/em> of the diamond, the \u2018cut\u2019 technically refers to the way the stone\u2019s facets interact with light. An expert will examine the way the proportions, symmetry and polish maximise the unique sparkle and brilliance of diamonds. The crucial point is how the facets\u2019 proportions influence the visual effects that count, including:
<\/p>\n\n\n\n- \n
- Brightness:<\/strong> Internal and external white light reflected from a diamond<\/li>\n\n\n\n
- Fire:<\/strong> The scattering of white light into all the colours of the rainbow<\/li>\n\n\n\n
- Scintillation:<\/strong> The \u2018sparkle factor\u2019, and the pattern of light and dark areas caused by reflections within the diamond<\/li>\n<\/ul>\n\n\n\n
GIA Cut Diagram<\/figcaption><\/figure>\n\n\n\n Colour
<\/h3>\n\n\n\nMany diamond colour distinctions are so subtle that they cannot be detected by the naked eye, but a completely pure, colourless diamond is considered to be of the highest quality and commands a higher price.
<\/p>\n\n\n\nThe GIA\u2019s D-Z colour-grading system ranks stones from completely colourless (D) to light yellow (Z). Diamonds whose natural colour falls outside of this spectrum are known as \u2018coloured diamonds\u2019 and are graded separately.
<\/p>\n\n\n\nCarat
<\/h3>\n\n\n\nCarat – named after the carob seeds used by early traders as counterweights – refers to the weight of the diamond. The metric weight (200mg per carat) is the same around the world. In principle, a larger diamond can command a higher price, but this is dependent on the condition of the stone as per the other three \u2018Cs\u2019.
<\/p>\n\n\n\nPoints<\/em><\/p>\n\n\n\n
You may hear a jeweller describe the weight of a diamond by its \u2018points\u2019. Each carat can be subdivided into 100 points. So a 0.25 carat diamond might be referred to as a \u2018twenty five pointer\u2019. Diamonds that weigh over one carat are expressed in carats and decimals – e.g. a \u2018one point two five carat\u2019 stone.<\/p>\n\n\n\n
Grading Antique Diamonds
<\/h2>\n\n\n\nWhen it comes to diamonds which have already been set (almost always the case when buying antique or vintage diamonds), you will need to apply a slightly different grading technique.<\/p>\n\n\n\n
Until universal diamond-grading was introduced by the GIA in the mid 20th century, nobody could agree on a single method for grading diamonds. For this reason, a technical grading is considered less important when buying antique and vintage diamonds. Different characteristics were prized at different times.
<\/p>\n\n\n\nWhen buying antique or vintage diamonds, it is more important to look for a piece of jewellery or a style that appeals to your aesthetic or historic interest than to look for a perfect stone.
<\/p>\n\n\n\nGrading antique and vintage diamonds is technically based on opinion unless the stones are loose (i.e. outside of their setting), but an expert will be able to give you a very good idea of the value of an old diamond using a magnifying loupe and expertise. They are graded using the same system as modern diamond grading – the \u20184Cs\u2019: Cut, Colour, Clarity and Carat. However, with antique diamonds you need to look for different traits to modern diamonds.
<\/p>\n\n\n\nHere\u2019s how it works:
<\/p>\n\n\n\nCut & Shape
<\/h3>\n\n\n\nAs with modern diamonds, the cut refers to the how the light interacts with the stone\u2019s symmetry, proportions and polish.
<\/p>\n\n\n\nThe shape of the stone refers to the outline of the stone – e.g. heart, round, marquise. The process of cutting a stone was intricate and required the serious skill of master artisans in the days before laser-cutting machinery.
<\/p>\n\n\n\nThe Old Cut diamond shapes evolved with advances in machinery and techniques. The most popular antique cuts include:
<\/p>\n\n\n\nRose Cut<\/strong><\/em><\/p>\n\n\n\n
Used since the 1600s, this beautiful, \u2018flat\u2019 cut worked with the natural shape of the stones and produced a demure, alluring sparkle.
<\/p>\n\n\n\nOld Mine Cut<\/em><\/strong><\/p>\n\n\n\n
Advancements in jewellery making resulted in a deeper pavilion (base) below the facets, which allow for a greater play of light within the diamond and a more brilliant sparkle.
<\/p>\n\n\n\nOld European Cut <\/em><\/strong><\/p>\n\n\n\n
The invention of the diamond-cutting wheel allowed for a perfectly round stone, opening up the diamond to even more light, creating even more sparkle and a wider array of patterns.
<\/p>\n\n\n\nOther common cuts in older jewellery include:
<\/p>\n\n\n\n- \n
- Pear Cut <\/li>\n\n\n\n
- Rectangular or Emerald Cut<\/li>\n\n\n\n
- Baguette Cut<\/li>\n\n\n\n
- Marquise cut<\/li>\n\n\n\n
- Heart Cut<\/li>\n\n\n\n
- Square or Princess Cut <\/li>\n\n\n\n
- Triangle or Trillion Cut<\/li>\n\n\n\n
- French Cut<\/li>\n<\/ul>\n\n\n\n
Antique Diamond Clarity Scale
<\/h3>\n\n\n\n<\/figure>\n\n\n\n
Flawless diamonds are incredibly rare and expensive even in modern diamonds. In past eras, carat was typically prized above clarity so it\u2019s very common for antique diamonds to be imperfect.<\/p>\n\n\n\n
An old, set diamond which is \u2018eye-clean\u2019 – Slightly Included – usually offers the best value, but it\u2019s worth considering that even an SI stone can only be identified under 10x magnification. <\/p>\n\n\n\n
Antique Diamond Colour Scale<\/h3>\n\n\n\n
<\/figure>\n\n\n\n
Just as with modern diamonds, truly white (colourless) antique diamonds are extremely rare and therefore expensive. Old diamonds usually have some colour in them, considered by many to add character and beauty to the stone. <\/p>\n\n\n\n
Keep in mind that an antique diamond\u2019s true colour can be affected by cutting techniques and when buying it\u2019s important to consider the piece of jewellery as a whole and look for stones you love rather than dismiss them due to their grading. <\/p>\n\n\n\n
Antique Diamond Carats<\/h3>\n\n\n\n
A carat is a measurement of weight equal to 0.20 grams. Bigger diamonds are rarer than small diamonds and this is typically reflected in the price of antique diamonds. However, diamonds can do what is known as \u201cfacing up larger\u201d, which means that looking at a stone straight on gives the illusion of a larger one. This is taken into consideration.
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- Fire:<\/strong> The scattering of white light into all the colours of the rainbow<\/li>\n\n\n\n
- Internally Flawless (IF)<\/strong> No inclusions visible under 10x magnification<\/li>\n\n\n\n
![\"GIA](\"https:\/\/lh3.googleusercontent.com\/z5qbv5VBybWvXh1_UYxLE8xzH-33Vgh8RVc23iHMa-cjsp0YStsPGVtppiTp1ITVmr9b2D_6vj1yXuW-J_ADKSeu_czGJSTf9wyY1qy_uklpg2F3sdBj0yDm9KJMuiHkLGZEABbZ\")
![\"GIA](\"https:\/\/lh4.googleusercontent.com\/2qT1y3zDpaJ21zYDqaLb1tZ9VKYfuUcl1Dk0r_u-xjEn1v-N37xJECBT3inTcsBQMqjci8mWk7pYEkFKWPlNmW-Np30mzoEXIWC5v7qImTIK_rdkID5V2VRfldwZ2OfHrL8erZ-D\")