About Diamonds
Diamonds are the cornerstone of a fair fraction of jewelry and jewelry appraisals, especially engagement rings. Often the diamond is sold separately from the ring for this reason.
Know About Diamonds First
Even if we’re looking at a style of setting where the focus is on some other type of gem, there are often smaller and remarkably expensive diamonds on the sides. There’s quite a bit of educational content online about diamonds and I’ll try not to replicate too much here that can easily be found elsewhere. Look at www.gia.edu, www.ags.org and www.pricescope.com for guides and tutorials along with the articles here.
In most cases, major diamonds are purchased separately from the rest of the ring, which is called the semi-mount. This system is for the benefit of both the jeweler and the customer. For you it means that the center diamond can be independently examined for damage, weighed, and lab graded for various attributes that price the stone. In nearly every case, I recommend doing this.
For the jeweler it means less inventory is needed to end up with exactly what the buyer wants. You pick a diamond, you pick a ring, and they assemble them in the shop. It’s easy, it’s fast, and they have the image of far more inventory. For Internet based vendors it’s even more important. They are almost certainly buying the mounting and the center diamond from two different sources. It will require assembly afterward, along with a resizing and possibly other modifications that you need. They couldn’t stock it as an assembled item, even if they wanted to.
Diamonds came onto the consumer jewelry industry in the 1880s with the discovery of the diamond fields in South Africa. Before that, the diamond engagement ring didn’t even exist and the jewelry business barely existed beyond royalty and the uber-rich. The marketing of diamonds, and in particular the efforts of DeBeers Consolidated Mines, changed everything. Within 30 years there was a jewelry store or 5 in every mall in the country. Diamond engagement rings became a component of nearly every marriage, and Hollywood stars became the new royalty, sporting diamonds everywhere they could.
About Diamonds - Technical Specifications:
What are the 4cs?
Cut, Color, Clarity, and Carat Weight are known as the 4C’s of diamonds. They’re part of the GIA grading scale developed in the 30’s to standardize buying and selling of diamonds. You’ll find several articles about diamonds on this general topic including the definitions of what the 4C’s are and, equally importantly, what they are not. They’re mentioned throughout the various tutorials and here’s a general overview about Diamonds.
Don’t buy blind. The 4C’s help but they are not the end of the story about diamonds. They’re the beginning.
From GIA:
Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value. (The exception to this is fancy color diamonds, such as pinks and blues, which lie outside this color range.) Most diamonds found in jewelry stores run from colorless to near-colorless, with slight hints of yellow or brown.
GIA’s color-grading scale about Diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown. Each letter grade has a clearly defined range of color appearance. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions.
Many of these color distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.
‘Clarity’ is determined by the visibility of microscopic inclusions and imperfections within a diamond. Diamonds with few to no inclusions are generally more expensive than stones where the presence of inclusions affects the beauty or durability of the stone.
From GIA:
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) – No inclusions and only 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 minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader under 10x magnification
Included (I1, I2, and I3) – Inclusions are obvious under 10× magnification and may affect transparency and brilliance
Diamond Carat Weight
Carat is the unit of measurement used to describe the weight of a diamond. It’s one way of measuring size. A carat is 200 milligrams or ⅕ of a gram. In general, the price of a diamond goes up in proportion to the weight.
Diamond Cut
Cut refers to the facets, symmetry, polish and reflective qualities of a diamond. It’s the part of a diamond’s grade that’s affected by man. Until recently, 2006, GIA didn’t have a scale for cut grade at all. What they chose is a bit complicated and, unlike the above, you can’t really tell the cut grade by looking, even under magnification. It requires some fairly exotic tools to know about diamonds in an accurate way.
Cut is where the most deviation happens between the various labs. IGI, another major lab, uses many of the same words but a very different scale. AGS doesn’t even use the same words.
From GIA:
The GIA Cut Grading System applies to the most popular cutting style – the standard round brilliant – and all clarities across the D-to-Z color range. There are five cut grades: Excellent (EX), Very Good (VG), Good (G), Fair (F) and Poor (P).
A diamond with an Excellent cut grade is very bright. It shows an even pattern with good contrast between light and dark areas, so the reflections appear crisp and well-balanced. This tells you that the cutter made the best possible use of the rough.
The Good cut grade diamond isn’t quite as bright – reflections aren’t as sharp and there’s more darkness or dullness in the diamond.
The Poor cut grade diamond has much more prominent dark areas or dullness. Given the choice, most people would pick either of the first two diamonds instead of this stone.
How to Read a Diamond Grading Report
When anyone is talking about diamond grading reports, or lab report, they mean one obtainable from the Gemological Institute of American (GIA) a short list of competitors.
Whether you are trying to buy or sell, be absolutely certain you have one.
Most buyers are interested in “current” lab reports from the last two years.
The Gemological Institute of America Sets the Standard
There are other Grading Reports out there, but when a gemologist, or a jeweler, or anyone really talking about diamonds they usually mean the Grading Report obtainable through the Gemological Institute of America. Alternatives are available from IGI and GCAL. Whether you are talking about Natural or Lab-Grown Diamonds, before you buy or try to sell, be certain you have a grading report. (Similarly, if you are trying to sell, get a Grading Report and an Independent Appraisal to make the process run smoother.)
The “Lab” or Lab Report. Not all labs are the same. This one is from GIA, the Gemological Institute of America, and is for a Natural Diamond. These differences are important. Most people mean this grading report when asking about Diamonds.
It is also important to note that there are grading reports for lab-grown diamonds as well as well as competitive labs like IGI and GCAL. For purposes of this article I’m going to be discussing GIA formatting. These competitive labs are similar but with their own differences.
Date. The date matters, even though it’s not a gemological property. If the report is from too long ago, there are concerns about possible damage that may have occurred since the inspection. Most shoppers are looking for a date within a year or two. It’s also worth noting that the information presented has changed over time. Older reports are a bit different. For example they don’t have a cut grade on reports about diamonds issued before 2006.
Report number. Every report issued by the GIA lab has a unique identifying number. They have an attached record that’s keyed to that number. For most stones inspected since 2010, you can look it up in their online database at www.gia.edu. For older stones they may be able to tell you more if you call them. 800-421-7250
Shape. Round, marquise, pear, etc. There are dozens of choices here. They also include modifiers like, “Modified round brilliant”. “Shape” is related to the 4cs of diamonds, though it is distinct from “Cut.”
Dimensions in Millimeters. Length x Width x Depth.
Weight in Carats. A carat is 200 milligrams and this is rounded to two decimal places, this is one of the 4cs of diamonds. In the lab, they use scales that are significantly more accurate than this but they round it off for purposes of the reports.
Color Grade. This refers to the 17-step GIA D-Z color grading scale as well as the grades they call ‘fancy’, the name they have for colored diamonds. Fancy grades will have a saturation grade as well as hue and possibly a modifier. This is one of the 4cs of Diamonds.
Clarity Grade. The 11-step clarity grading scale, from Flawless to I3. This is one of the 4cs of Diamonds.
Cut Grade. GIA currently only supplies a cut grade on Modern Round Brilliant cut diamonds. All others will eliminate this line entirely. This is one of the 4cs of Diamonds. If you’re interested in Cut Grading for a diamond with a different shape, see an independent appraiser or one of the other labs, like IGI, that offer a cut grade on other shapes. It’s tricky because they all use systems that are unique to them and there is far from agreement on what makes the most ‘ideal’ cut.
Polish. Excellent, Very Good, Good, Fair, Poor.
Symmetry. Excellent, Very Good, Good, Fair, Poor. Geometric symmetry.
Fluorescence. None, Faint, Medium, Strong, Very Strong along with a color modifier. This is the stone’s reaction to ultraviolet light.
Inscription. Some but not all diamonds will have an inscription on the girdle. If present, it will be quoted here. If not it will list ‘none’. There may be inscriptions on the stone that were added AFTER the lab inspection.
Comments: These are notes that the grader though might be important. Laser drill holes, treatments, and special phenomena like phosphorescence, are examples. This is also where you’ll see grading characteristics like ‘cloud not shown’ that don’t appear in the diagram.
Proportion diagram. Some of these are averages, like crown and pavilion angles while some, like the culet, have a word description. Not all GIA report formats include this.
Plotting diagram. This will be a map from both the top and back view to locate the clarity characteristics that were used to set the grade or that may be useful in identifying the stone.
Key to Symbols. This is a list of what led to the clarity conclusion in item #8 above and the diagram in #15 above. They appear in order of what the grader thought was important. A list of the available symbols and therefore what they didn’t see, or at least didn’t use, is here.
Scales. This is a list of the clarity, color, and cut scales according to the 4cs of Diamonds.
QR Code. This will link to the GIA record for that particular stone.
Beyond The 4c’s
Yes, there are more than 4. Diamond grading is a rabbit hole for shoppers and it’s easy to get lost. They are a blind item and the more you look the more you find to learn. Cut, in particular, is a tricky topic to navigate but Country of Origin, and Certification are big topics as well.
This scale only applies to natural diamonds. Lab grown diamonds have different sorts of inclusions as well as some different attributes, like method of manufacture.
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