diamond grading Archives

A Guide to Diamond Inclusions and Blemishes

When carbon is exposed to extreme amounts of heat and pressure deep within the earth, the end result is the creation of a natural diamond. This strenuous process can leave a variety of characteristics upon a diamond crystal. Those features enclosed within the gemstone are referred to as inclusions and those left on the exterior are called blemishes. The Clarity Grade of a given diamond, one of the 4Cs, is determined by the presence or absence of these features.

Inclusions, or internal characteristics, will appear during the diamond’s formation. Inclusions will be unique for every single gemstones, essentially giving your diamond a fingerprint that allows you to recognize it apart from all others. There is a variety of inclusions, but the most common types we come across are clouds, feathers or mineral crystals enclosed within a gemstone.

Blemishes are characteristics confined to the exterior of a diamond. Blemishes can occur naturally, or be man-made resulting from the cutting process a faceted gemstone endures.

The severity of a stone’s inclusions and blemishes with determine its clarity grade. The number, size, relief, nature, and position of characteristics are taken into consideration when formulating a diamond’s clarity as it is recorded on its certification. No diamond will be perfectly pure, each gemstone will have some residue from its creations. However, the closer a diamond is to pure, the more rare and valuable it will become.

The GIA Diamond Clarity Scale has six categories, divided into a total of eleven specific grades.

Flawless (FL) – No inclusions and no blemished viable under 10x magnification.
Internally Flawless (IF) – No inclusions viable under 10x magnification.
Very, Very Slightly Included (VVS1 and VVS2) – Inclusions so slight they are difficult for skilled grader to see under 10x magnification.
Very Slightly Included (VS1 and VS2) – Inclusions are observed with effort under 10x magnification, but can be characterized as minor.
Slightly Included (SI1 and SI2) – Inclusions are noticeable under 10x magnification.
Included (I1, I2, and I3) – Inclusions are obvious under 10x magnification which may affect transparency and brilliant.

Married to a Clarity Grade on a diamond grading report is a Plotting Diagram. This diagram displays important diamond characteristic information that was seen during the grading process. It is essential a map that tells a deeper story about your center stone. All of a diamond’s important inclusions and blemishes are documented and plotted. Since no two diamonds will have exactly the same diagram, this map will be important in identifying your gemstone if ever need be.

The plotting diagram will roughly resemble the shape and faceting pattern of your diamond. This helps you to understand where the marked characteristics are located on your gemstone. There will be two views shows of the diamond. Its crown view, or top, and pavilion view, or bottom.

In a plotting diagram, a certain color will correspond to each category of clarity characteristics. The colors and symbols used will help you understand the nature of each feature.

Red – Inclusions
Red and Green Combined – Inclusions that reach the surface of the diamond like; cavities, indented naturals, knots or laser drill holes.
Green – Natural Blemishes
Black – Extra Facets

The diagram below lists common characteristics as they would appear on a GIA plotting diagram. When characteristics are listed on a cert they will appear in order of importance to the clarity grade. If a large, centrally located feather is present in your stone, with few other impediments, it will be seen first in the list of inclusions. This feather most likely determined the final clarity grade of your diamond.

plotting-diagram-characteristics-321x1024 Unique Engagement Rings — GIA Plotting Diagram Key

Some clarity characteristics in a diamond may not be plotted on their certification if they are faint or are not important in determining the clarity grade of a gemstone. Featured that are not diagrammed will often be listed in the Comments section of the certification.

A GIA Plotting Diagram is an important tool in understanding the one-of-a-kind characteristics present in your perfect diamond. Keep in mind, that many characteristics are too small to be seen by anyone apart from a trained diamond grader. To your naked eye, two diamonds may look similar even though they drastically differ in grades. What is important is to choose a center stone that speaks to you with the quality standards you desire.

Here at Knox Jewelers, we want to assist you in finding your perfect center stone to feature in one of our custom created settings. You may not desire that gemstone to be a diamond, but if you do, we will walk you through the important features present in the diamond you choose. Contact us today to start the hunt for your perfect diamond, no matter the shape, size or color.

How to Read a GIA Diamond Grading Report

So you’re ready to propose to the love-of-your-life with a Knox Custom Engagement Ring, but you want to be positive you’ve chosen the best possible diamond. Knox Jewelers recommends selecting a diamond evaluated by GIA to ensure the diamond comes with a detailed graded report. A GIA Diamond Grading Report is the standard for evaluating diamonds and their quality. Don’t know how to read a GIA Diamond Grading Report? Don’t worry, Knox will always help you learn everything about your diamond selection, either in-store or online.

GIA stands for Gemological Institute of America. It is a public and independent benefit institute that was established in 1931. They are the leading source of knowledge, standards, and education when it comes to gems and jewelry. GIA is the creator of the “4 Cs” (Color, Clarity, Cut, and Carat Weight) and the International Diamond Grading System that maintains the methods and best practices for describing diamond quality. Today, virtually everyone in the international diamond industry uses these methods for comparing and evaluating diamonds. A grading report from GIA is more than a collection of observations about a gem. It represents an accurate and unbiased, comprehensive scientific investigation.

Let’s review the main components of a GIA grading report.

Each diamond evaluated by GIA is assigned a unique GIA Report Number which you can use to look up your report online.

A diamond’s Shape refers to its face-up outline. Popular shapes include round, square, oval, rectangle and pear.

Cutting Style refers to a stone’s faceting pattern. Brilliant-Cut diamonds contain a large number of small, triangular shaped facets. These include Round Brilliant, Princess and Ovals cut gems. Step-Cut diamonds contain larger, long, rectangle shaped facets. These include Emerald and Asscher cut gems.

A diamond’s Measurements will be listed in the order of smallest width, largest width and height.

The Weight of a diamond is measured in a form called carats. GIA reports a diamond’s carat weight to the nearest hundredth of a carat. To give you some perceptive, 1 carat is equal to 0.20 grams.

The GIA Color Grade system describes the diamond’s lack of color by ranging from the denotation D, which is colorless, all the way to Z, which will be a shade of either light yellow or brown. Color grades from D to F are considered colorless diamonds and G to J are near-colorless.

Diamond Clarity evaluates the size, the number, relief, nature, and position of internal inclusions and surface blemishes. The Institute assigns one of eleven clarity grades to a diamond. This can range from the clarity grade of flawless to that of included and lists the most prominent clarity characteristics. Stone graded VS2 and above should be eye-clean, with inclusions only seen under magnification.

On some report formats, Clarity Characteristics are shown as a plotted diagram, marking significant or identifying characteristics. A key lists the relevant symbols and their definitions. Red symbols stand for inclusions, which characteristics inside a stone. Green or black symbols stand for external characteristics on the diamond, or blemishes.

For the standard round brilliant diamond, GIA assigns a Cut Grade ranging from Excellent to Poor. Diamonds can be Excellent, Very Good, Good, Fair, or Poor. This grading takes into account seven components; Polish, Symmetry, Weight Ratio, Durability, Brightness, Fire, and Scintillation.

The diamond’s Proportions are thoroughly described as well, from its shape and cutting style to its precise measurements. A diagram will show you the diamond’s profile as well as its dimensions.

A description of Fluorescence is provided as an additional identifying characteristic. GIA tests every diamond to ensure that it is natural and to identify any processes that may have been used to alter its color or clarity. An asterisk next to the color or clarity grade indicates that the diamond has been treated. Treatments and additional identifying characteristics are described in the comments section.

If the diamond is inscribed, the Inscription will be noted on the report as well. A GIA Grading Report has a number of sophisticated security features designed to ensure its authenticity and integrity. They offer a variety of diamond reports, among them the Diamond eReport, an interactive online option available only for natural and untreated diamonds(perfect if you want to search for beautiful custom diamond engagement rings from the comfort of your home). The Institute operates under strict standard procedures and principles designed to ensure objectivity and accuracy, no matter which report you receive.

That’s how to read a GIA Diamond Grading Report! It’s not as intimidating as you might think. Selecting the perfect ring among many beautiful custom diamond engagement rings might be another story. Luckily, Knox Jewelers can help you look at a variety of rings and narrow it down to the perfect one for your lucky life partner. GIA Diamond Grading Reports are also available! Let Knox Jewelers help you learn about diamonds so you can pick the perfect diamond that meets the color, clarity, cut, and carat weight that you desire and help give your engagement a beautiful start.

Understanding the 5th “C” in Diamond Grading: Certification

Could you imagine going into a car dealership purchasing what you thought was a 6 cylinder luxury performance car, only to discover it was actually a 4 cylinder engine with the body of a sports car. This misrepresentation would never occur in the auto industry. However falsely identified diamonds are common in the jewelry industry. The idea that all diamond laboratories are created equal is not the case; while most labs use the GIA diamond grading scale, not all have the same level standards to adhere to it.

home_diamond_4cs-300x262 Diamonds — GIA's 4C's of Diamond Quality

Many industry leaders have tested this known truth of variable diamond grading standards by sending the same diamond to different labs and getting very different results. Rapaport, an international network that provides an overview of the diamond market, recently preformed one of these studies using 10 diamonds. The diamonds were sent to different grading labs in the US and abroad. The outcome proved that some diamonds could differ as much as three color grades when graded at multiple labs.

The biggest difference in these grading reports were American labs verses international. Surveys found grading labs in the US, including GIA, IGI, and EGL USA were fairly close in their grading standards. However, EGL USA generally graded the diamonds much more lenient than the other two labs.

Another discrepancy in the diamond reports were the laboratories overseas, including EGL Israel and EGL Hong Kong. This is when they found some diamonds two to three color grades off when compared to diamond reports from the US. Antwerp’s HRD lab was slightly softer in grading when analyzed to GIA standards.

So many labs are speaking the same diamond language but each with varying interpretations. How is a consumer to know they are truly purchasing an “E” color diamond and not an “H?” The biggest safeguard for a consumer is to be educated on diamond quality.

Color-Scale_BlogCanvas-300x185 Diamonds — GIA Diamond Color Scale

At Knox, educating our customers on the 4C’s and showing how to identify differences in quality is how we maintain consumer confidence. Once you can detect a colorless diamond from a near colorless diamond, you will gain the security of knowing how to select diamond color. Knox Jewelers will spend time with you, going over internal features of clarity characteristics using a microscope or loupe; helping to understand the clarity scale and what that represents in a diamond. During a diamond consultation we express the importance of a well cut diamond and how that relates to the overall beauty of a stone. At that time, we emphasize how to select a diamond size based on its dimensions and not by carat weight alone.

By knowing what diamond characteristics to look for, customers have the knowledge in determining the true nature of a diamond and if the lab certification is accurately supported. Most diamonds are laser inscribed on the girdle of the stone, this is the outer edge that separates the top and bottom portion of a diamond. This inscription is a sequence of numbers and letters that identifies the diamond with the laboratory’s certification report. If this inscribed code coordinates with the lab report number, customers can be confident the information being presented is genuine.

When evaluating the authenticity of a diamond report, it is important to understand who is certifying the stone. GIA was the pioneer in establishing the grading scale and providing third party verification on diamonds. Their strict grading procedures is well respected in the jewelry industry. With this reputation, high quality diamonds are sent to GIA for certification. While diamonds of lower value are sent to labs with soft grading practices in an effort to achieve higher diamond grades than GIA would evaluate the diamond at.

gia_lab1-200x300 Diamonds — A GIA Diamond Grader Evaluates Diamond Quality

With this understanding, Knox Jewelers prefers the highly recognized, honest services provided by GIA. We choose not to sell diamonds that are overly generous in their diamond evaluations. As a small, locally owned business located in Minnesota we wholeheartedly believe in the integrity of our family jewelery store. GIA is the world’s most trusted name in diamond grading. In line with Knox Jewelers higher level of standards, GIA ensures the integrity and accuracy of every report it issues with objectivity and expertise. To display the very best of diamond attributes, choose a GIA graded diamond for your Knox ring.