We believe that man-made diamonds are created differently, and they possess certain inalienable features, among which are color, clarity, cut, and carat weight.
Lab-grown diamonds differ in their 4C’s, just like mined diamonds, and, therefore, grading is necessary. Most mainstream gemological labs offer grading and certification services for lab-grown diamonds to businesses, but some issues have arisen with certain labs.
Here is a list of other reputable institutions for gemological analysis and certification.
- CIBJO - Confederation International de la Bijouterie, Joaillerie, Orfevrerie des Diamantes, Perles at Pierres. (aka "International Confederation of Jewellery, Silverware, Diamonds, Pearls and Stones"). CIBJO has about 95 members in 27 countries, although not all of these operate a diamond laboratory. There are 14 CIBJO labs in 12 countries.
- Higher Diamond Council (HRD), in Antwerp, Belgium.
- The Gemmological Association and Gem Testing Laboratory of Great Britain (GAGTL), or Londen Gem Lan.
- The European Gemological Laboratory (EGL).
- International Gemological Institute (IGI), located in Belgium and the USA.
- American Gemological Society (AGS) Laboratory in Las Vegas.
- The Gemological Laboratory of Israel (IDI, formerly GILI) in Ramat Gan.
The majority of laboratories utilize one of the two primary grading systems:
Each system has its own unique methodology and nomenclature for effective gemstone evaluation. On the back of the certificate form, tables can often be found to translate these grading systems into one another. Performing a conversion is simple since the color and clarity grade boundaries coincide. Nonetheless, it's possible for different laboratories to assign different qualities to the same diamond.
In the US market, the most reputable gemological laboratories are GIA and AGS, which use their own compatible grading systems. EGL USA Gemological Laboratory stands out among other American gemological expert organizations.
The GIA and AGS grading systems were established at close intervals in the same regional market area, but are based on different grading principles. The GIA grading system was established in 1953 and focused on the traditional approach to diamond grading. The AGS grading system was established mainly in 1966 and is also based on the traditional approach to grading, but the approach to color standards has been standardized on the basis of electronic colorimetric data (taking into account arbitrated assessments of standards selected using electronic calorimeters).
Since 1996, as part of the program to unify the AGS and GIA diamond grading systems, the values of the color standards in the AGS system have been brought as close as possible to the GIA standards (but the definition of their boundaries is determined according to the priority of the colorimetric measurement intervals). In accordance with the GIA grading system, photometric measurements may be considered, but are not decisive for the qualitative characterization of a diamond's color.
Since the end of 2022, AGS has been absorbed by the Gemological Institute of America (GIA).
When trading certified diamonds, it is crucial to understand that certificates obtained from various laboratories and systems can have varying treatment across different countries and dealers. It is imperative to choose the appropriate certification body for your diamond, as it undergoes certification only once. Additionally, the cost of certification services depends on the laboratory's authority and is typically between 1-5% of the stone's value. The price of a certified diamond is typically higher than that of a non-certified diamond, and it also has higher liquidity.
Certifying small or inexpensive diamonds is not practical. Laboratories usually accept stones that are 0.47 carats and above (GIA accepts stones that are 0.21 carats and above.) Certifying large wholesale lots, as well as stones in articles, is relatively uncommon.
Certifying large wholesale lots and stones in products is uncommon.
Imitation diamonds, cut stones, and compound stones are not eligible for certification.
You should know, that GIA only categorizes color and clarity rather than specifying exact values, which can cause confusion and lead to significant price discrepancies. For instance, 1ct D VS1 Round stone might cost around $3500. But 1ct F VS2 Round stone is gonna be around $2500. However, both stones will be considered Colorless Very Slightly Included by GIA.
IGI accurately grades lab-grown stones. At the same time, GCAL also states Hearts & Arrows specification.
In Europe, HRD reports are prevalent, and they use their grading scale.
Diamond certification procedures are generally similar in labs worldwide, with variations primarily in technology.
This section examines certification procedures through two renowned laboratories: the High Diamond Council of Belgium (HRD) and the Gemological Institute of America (GIA GTL).
After the examination, the lab issues an expert report called the "Diamond Aerop." For smaller stones or on the customer's request, a shortened version of the report, named the "Diamond Dossier," is also available. The GIA laboratory certifies diamonds by examining their main characteristics, which include color, clarity, proportions, and quality of finishing.
Diamonds submitted for examination undergo analysis by at least five and sometimes up to twelve experts. The process of examining a diamond includes several stages: preliminary examination, expert evaluation, color assessment, and determination of coloration (for colored stones).
During the preliminary examination, special high-precision equipment is used to determine the diamond's weight and dimensions. The stone is then positioned in a transparent container until the end of the examination. A document containing the weight, dimensions, identification numbers, necessary services, and instructions for the item has been affixed to the container. The client's identity remains undisclosed to guarantee anonymity throughout the expert appraisal process.
The evaluation of the diamond involves the determination of clarity, symmetry, and finishing quality while also marking the clarity characteristics on specific charts pertaining to the diamond's cut. At this stage, two experts work individually with the stone, storing their data on a computer. The data is then reviewed and combined to generate a final result.
Two experts also collaborate to determine the stone's color properties by comparing it to reference diamonds, and recording the results in the computer. The third expert examines the data and provides the final outcome.
The evaluation of the color of fancy colored diamonds is conducted by a specialized group of experts who specialize in assessing colored diamonds. The stones undergo analysis with a Macbeth Judge II viewing device and compared with hundreds of reference stones. Utilizing state-of-the-art research methods, two experts determine whether the diamond's color is natural or of artificial origin.
At the completion of these procedures, the GIA produces a comprehensive expert report which includes detailed information such as diamond size, weight, proportions, color, polish quality, and clarity characteristics. Additionally, the report contains a chart illustrating the type of cut for clarity assessment.
After the report is ready, the stone and the GIA report are returned to the owner in the same package in which they were delivered to the laboratory.
Registration. Diamonds to be assessed are recorded and weighed to the nearest 0.0001 or 0.0005 ct. The laboratory issues a confirmation to the client, containing a record of the diamond's weight and further traits that are stored on the laboratory's computer. At the end of the certification process, the diamond is given a unique number for identification purposes, and the owner is invoiced for the laboratory's services.
Lab treatment is also undertaken. The diamond is cleansed using alcohol and pumice powder. Prior to examination, the stone will require washing in sulfuric acid. Routine identification procedures, such as using a thermal conductivity meter, are conducted to verify authenticity.
Fluorescence testing follows, whereby the diamond is exposed to long-wave UV light in a specialized unit before being compared to reference stones.
Color grading. Diamonds can be categorized according to their color into the “Cape” series, which is characterized by a yellow hue, or as fancy colored diamonds. To classify a diamond into the “Cape” series, it is visually compared to a set of reference stones in a laboratory under standard lighting conditions. To determine the color group, there must be complete agreement on at least four separate assessments. Fancy colored diamonds are graded based on visual comparison to color charts. The stones undergo both spectrophotometric and spectrofluorimetric analysis to verify their natural color origin. Findings from these tests are used to issue a Colored Diamond Report, a bespoke document intended for fancy colored diamonds.
For clarity assessment, the diamond is meticulously scrutinized under an HRD grading microscope that utilizes a unique illumination system and mechanism to hold the stone. Internal flaws are evaluated using a grid placed on the microscope's eyepieces. The quantity, size, brightness, location, and the number of facets revealing them are all considered when determining purity. The table assessing all of these factors, degree of transparency, structural and surface defects, is used in selecting the clarity group. The diamond is inspected using a 10x triplet loupe to confirm that its clarity meets international standards. The assessment of clarity is conducted by three assessors who work independently of each other.
A diamond cut evaluation includes assessing proportion and finish. We determine any deviations in symmetry that could impact the stone's appearance using a proportion scope, micrometer, and HRD microscope. Proportions are only evaluated for brilliant round diamonds, while other cut shapes are measured for proportions but aren't assessed with generally accepted standards for fancy cut shapes. The last step in quality control involves evaluating the diamond cut using a 10x triplet magnifying glass.
A certificate is then issued to the client, considering the laboratory tests and analyses, as well as the data stored in the computer. The diamond is returned to the client's package or in a special plastic package that is sealed along with the microfilm of the certificate. A unique seal ensures the conformity of the stone and certificate.
LaBrilliante lab made diamonds are certified with same 4c's as natural diamonds by same 3rd party institutions like IGI, HRD, EGL, etc.
Yes, a diamond with a certificate will cost more than a similar stone without a document. Depending on the laboratory, a passport will add 20-150% to the price. This is your fee for not having to risk buying a fake diamond or a stone with inflated characteristics.
Certification is a paid procedure, not all sellers want to incur additional costs. If the stone is of low quality, small and the document will not matter to the buyer, certification is again not done. The last reason is the seller's desire to overestimate the characteristics of the stone and sell it for more than its real value. With a certificate, he will not be able to do this.