My Pink Diamonds

Diamond Cut…The Basics: Step 1 – Understanding diamond “certs”Chapter 2If you are going to purchase a diamond, and know what you are getting when you purchase it, you need to be able to understand the information that is presented on a “lab grading report”, and how the information was obtained. Having this knowledge will further assist you to know if any follow up/independent data, presented to you by the jeweler, in conjunction with a “lab grading report”, is valid and accurate. Here are several examples of “lab grading reports”. To gain a better understanding of how information is broken down on a lab report, we will examine one line by line. NOTE: We will not be discussing the relevance of this information to the diamond’s cut quality, as that will be done in detail later on in this tutorial. GIA Lab Grading ReportFigure 2.1

EGL USA Lab Grading ReportFigure 2.2

For the purposes of this tutorial, we will examine the AGS Lab Grading Report. Most reports have similar information on them and are simply arranged differently. Immediately below is the full copy of the “lab grading report”. Since the lettering on this report is quite small, we have included enlarged portions of the report below that will allow us to examine the information contained in this report more closely.AGS Lab Grading ReportFigure 2.3

Figure 2.4

Figure 2.5

Figure 2.6

If we examine Figure 2.4, we see that this area of the report displays the basic information about the diamond. Let’s break this down point by point•    Shape and Style

•    Measurements

•    Cut Grade

•    Color Grade

•    Clarity Grade

•    Carat Weight

NOTE: A very important fact to understand about Color and Clarity is that the grading standards vary widely from on grading laboratory to another. Some of have much stricter standards than others, and this is something that should be carefully considered before purchasing a diamond. Looking at Figure 2.5, we can see a proportion map of the diamond, with basic proportion and measurement data. The first thing that we notice when looking at this, is that the only two standards of measurements used are Percentages and Degrees. The very first measurement of the diamond is the 100%, which is equal to the average diameter of the stone at its widest point, the girdle. It is based off of this percentage that all of the other percentage measurements are calculated.Directly under this measurement, we can see the 55.4% measurement. This is the diameter of the Table Facet, expressed in a percentage of the total average diameter. The vertical line along the left had diamond is the measurement of the Total Depth of the diamond, again, expressed as a percentage of the total average diameter, in this case, 61.9%The vertical line along the right side of the diamond, broken into three different measurements essentially breaks down the factors that make up the total depth of the diamond. These three factors are called Crown Height, Girdle Thickness, and Pavilion Depth.  In this case you can see the three measurements are as follows.•    Crown Height – 15.5%•    Girdle Thickness – 1.6% to 4.4%•    Pavilion Depth – 42.8%The two angle measurements on the left hand side of the graph are the Crown Angle and Pavilion Angle measurements. In this case, the Crown Angle is 34.8 degrees, and the Pavilion angle is 40.6 degrees.The two numbers in the diamond represent facet length measurements.  The measurement in the small facets on top is the Star Facet Length, and the measurement in the slightly larger facets on the bottom is the Lower Girdle Facet Length. For this diamond, the Star Facets measure 51% and the Lower Girdle Facet’s measure 75%. It is very important to understand that these two percentages are not calculated against the total depth. Rather Star Facet Lengths are expressed as a percentage of the total distance between the edge of the Table and the edge of the Girdle. Lower Girdle Facet Lengths are expressed in a percentage of the total distance between the Culet and the edge of the Girdle. (See illustration below)Star Fact MeasurementThe Green arrow, in Figure 2.7, represents 100% of the distance from the edge of the TABLE to the edge of the GIRDLE. The STAR FACET measurement is expressed as a percentage of the total measurement.Figure 2.7

Lower Girdle Facet MeasurementThe green arrow in Figure 2.8 represents 100% of the distance between the edge of the GIRDLE and the CULET. The LOWER GIRDLE FACET measurement is expressed as a percentage of the total measurement. Figure 2.8

Lastly at the bottom, we see the Culet Size. This is almost always expressed as a word. Culet sizes vary including sizes of None, Pointed, Very Small, Small, Medium, etc.The last graphic we see, Figure 2.6, is the Clarity Plot of the diamond. This is where the grading inclusions, that were visible at 10x magnification, are plotted by the grader. Clarity has already been discussed in brief in the Emma Parker & Co. Diamond Tutorial, however there are some simple hints to help you spot important information on the Clarity Plot. All inclusions plotted in RED INK are INTERNAL inclusions. All inclusions plotted in GREEN INK are EXTERNAL inclusions. This basic walk through of the information that is listed on a lab grading report will give you a good foundation in what information you will be presented with later on in this tutorial, and what each measurement relates to. In the following chapters we are going to dig deeper into cut, what to look for in a great cut, what tools and reports are useful in looking for a good cut and how to read them, and more. Written by Timothy Andre, Emma Parker & Co.     www.emmaparkerdiamonds.com

Diamond Cut…The Basics: Step 1 – Understanding diamond “certs”Chapter 2If you are going to purchase a diamond, and know what you are getting when you purchase it, you need to be able to understand the information that is presented on a “lab grading report”, and how the information was obtained. Having this knowledge will further assist you to know if any follow up/independent data, presented to you by the jeweler, in conjunction with a “lab grading report”, is valid and accurate. Here are several examples of “lab grading reports”. To gain a better understanding of how information is broken down on a lab report, we will examine one line by line. NOTE: We will not be discussing the relevance of this information to the diamond’s cut quality, as that will be done in detail later on in this tutorial. GIA Lab Grading ReportFigure 2.1

EGL USA Lab Grading ReportFigure 2.2

For the purposes of this tutorial, we will examine the AGS Lab Grading Report. Most reports have similar information on them and are simply arranged differently. Immediately below is the full copy of the “lab grading report”. Since the lettering on this report is quite small, we have included enlarged portions of the report below that will allow us to examine the information contained in this report more closely.AGS Lab Grading ReportFigure 2.3

Figure 2.4

Figure 2.5

Figure 2.6

If we examine Figure 2.4, we see that this area of the report displays the basic information about the diamond. Let’s break this down point by point•    Shape and Style

•    Measurements

•    Cut Grade

•    Color Grade

•    Clarity Grade

•    Carat Weight

NOTE: A very important fact to understand about Color and Clarity is that the grading standards vary widely from on grading laboratory to another. Some of have much stricter standards than others, and this is something that should be carefully considered before purchasing a diamond. Looking at Figure 2.5, we can see a proportion map of the diamond, with basic proportion and measurement data. The first thing that we notice when looking at this, is that the only two standards of measurements used are Percentages and Degrees. The very first measurement of the diamond is the 100%, which is equal to the average diameter of the stone at its widest point, the girdle. It is based off of this percentage that all of the other percentage measurements are calculated.Directly under this measurement, we can see the 55.4% measurement. This is the diameter of the Table Facet, expressed in a percentage of the total average diameter. The vertical line along the left had diamond is the measurement of the Total Depth of the diamond, again, expressed as a percentage of the total average diameter, in this case, 61.9%The vertical line along the right side of the diamond, broken into three different measurements essentially breaks down the factors that make up the total depth of the diamond. These three factors are called Crown Height, Girdle Thickness, and Pavilion Depth.  In this case you can see the three measurements are as follows.•    Crown Height – 15.5%•    Girdle Thickness – 1.6% to 4.4%•    Pavilion Depth – 42.8%The two angle measurements on the left hand side of the graph are the Crown Angle and Pavilion Angle measurements. In this case, the Crown Angle is 34.8 degrees, and the Pavilion angle is 40.6 degrees.The two numbers in the diamond represent facet length measurements.  The measurement in the small facets on top is the Star Facet Length, and the measurement in the slightly larger facets on the bottom is the Lower Girdle Facet Length. For this diamond, the Star Facets measure 51% and the Lower Girdle Facet’s measure 75%. It is very important to understand that these two percentages are not calculated against the total depth. Rather Star Facet Lengths are expressed as a percentage of the total distance between the edge of the Table and the edge of the Girdle. Lower Girdle Facet Lengths are expressed in a percentage of the total distance between the Culet and the edge of the Girdle. (See illustration below)Star Fact MeasurementThe Green arrow, in Figure 2.7, represents 100% of the distance from the edge of the TABLE to the edge of the GIRDLE. The STAR FACET measurement is expressed as a percentage of the total measurement.Figure 2.7

Lower Girdle Facet MeasurementThe green arrow in Figure 2.8 represents 100% of the distance between the edge of the GIRDLE and the CULET. The LOWER GIRDLE FACET measurement is expressed as a percentage of the total measurement. Figure 2.8

Lastly at the bottom, we see the Culet Size. This is almost always expressed as a word. Culet sizes vary including sizes of None, Pointed, Very Small, Small, Medium, etc.The last graphic we see, Figure 2.6, is the Clarity Plot of the diamond. This is where the grading inclusions, that were visible at 10x magnification, are plotted by the grader. Clarity has already been discussed in brief in the Emma Parker & Co. Diamond Tutorial, however there are some simple hints to help you spot important information on the Clarity Plot. All inclusions plotted in RED INK are INTERNAL inclusions. All inclusions plotted in GREEN INK are EXTERNAL inclusions. This basic walk through of the information that is listed on a lab grading report will give you a good foundation in what information you will be presented with later on in this tutorial, and what each measurement relates to. In the following chapters we are going to dig deeper into cut, what to look for in a great cut, what tools and reports are useful in looking for a good cut and how to read them, and more. Written by Timothy Andre, Emma Parker & Co.     www.emmaparkerdiamonds.com

The reason that it is so important to understand that uniqueness of diamonds, the difficulty with which the cutting process is fraught, the immense variation in cut grading, and the application of scientific tests, is that this understanding is imperative to gaining a full comprehension of diamond “certs”, how they are produced, and why there are so many conflicting opinions in the industry.The diamond “cert” as it has become known, is in actuality, not a certificate, as the name would suggest, but is rather a report issued by the gemological laboratory that was paid, by the diamond’s owner, to grade the diamond. The report, commonly called the “cert” (this will be referred to as a “lab grading report” for the remainder of this tutorial), is a printed record of the gemological lab’s determinations as to the quality of the diamond. The findings, although based on a scientific grading system, are really a codified representation of a subjective grading analysis that was performed by one or several human graders, each subject to their own grading style and grading predispositions. Each gemological laboratory has its own individual grading process, that stems off of its unique grading protocol, using its own predetermined course of grading procedures, and employing its own preselected scientific equipment for testing and observing the stone in question.The fact that there are many different gemological laboratories, each with its own grading system, has lead to a wide variety of “lab grading reports” being issued on diamonds, and presented to the general consumer as absolute fact about the quality of the diamond being purchased.Of course, at this point, the question must be asked…why are there so many standards…and why has no single standard been determined?  The answer is quite simple. Most consumers, when presented with a “lab grading report”, are wiling to take the information being presented about the stone at face value, many times with little or no knowledge about the gemological laboratory, its grading practices and procedures, or its reputation in the market place. This action by consumers, and the fact that retailers are aware of this fact, has lead to a very simple, yet very detrimental trend in the diamond grading industry. Consider this…if the average consumer takes a “lab grading report” at face value, without regard to the quality of the grading performed by the lab; and the value of a diamond rests almost entirely, excepting its weight, on areas of subjective grading; i.e. cut quality, color, and clarity; a lab that grades on a loose standard (issuing reports that give diamonds a slightly better grade than the lab’s stricter competitors would give) would allow retailers to present a “lab grading report” that is more “favorable” as well as giving them the ability to charge a higher price for a lower quality stone. The main basis for many labs that grade based on loose criteria is that of consumer ignorance. Diamond cutters, wholesalers, and retailers use these labs to grade their diamonds in an effort to increase the value and salability of their inventory, with the by-product of this effort being added expense to the consumer. It is imperative that, as a consumer, you have a solid understanding of the major gemological laboratories in the market, their grading systems, and their reputations for the accuracy of the “lab grading reports” that they issue. Below is a short list of the major gemological laboratories, in the basic order of their grading strictness.NOTE: It is important to remember that diamond grading is done by humans, which means that human error is a possibility. It is possible for any gemological laboratory to make a mistake in the grading of a diamond. Diamond Grading Laboratories•    American Gemological Society Laboratory (AGSL or AGS)•    Gemological Institute of America (GIA)•    Gem Certification and Assurance Lab (GCAL)•    HRD Antwerp•    European Gemological Laboratories USA (EGL USA)•    European Gemological Laboratories (EGL)•    European Gemological Laboratories Israel•    International Gemological Institute (IGI)Written by Timothy Andre, Emma Parker & Co.     www.emmaparkerdiamonds.com