Certified Loose Diamonds by GIA Diamond Institute
The Gemological Institute of America, or GIA, is a non-profit institute dedicated to research and education in the field of gemology. The GIA is also well known for its gem identification and grading services, and developed the famous "Four C's" (Cut, Clarity, Color and Carat weight) methodology of grading diamonds. The educational arm of the GIA confers the Graduate Gemologist diploma upon its graduates; the institute also offers other diploma programs. The GIA was founded in 1931 by Robert Shipley in Los Angeles, California. Today, the institute is headquartered in Carlsbad, California, north of San Diego.
GIA Diamond Certificate
Through its arm the GIA Gem Trade Laboratory, GIA provides diamond grading services to describe the characteristics of loose diamonds. The GIA issues two types of reports, the more complete being the Diamond Grading Report (a briefer and less expensive version is called a Diamond Dossier). The Diamond Grading Report identifies the key characteristics of a diamond which can be used to both identify the diamond and determine its value. The reports contain a number of measurements, including of carat weight and critical angles, as well as a diagram of where and what types of inclusions are located in the diamond. This type of report is now offered by competitors to GIA, although GIA's reports are widely considered to be the strictest and therefore most reputable available. Diamond grading reports are now demanded by most consumers purchasing diamonds over a certain size, typically for over 0.5 carat (100 mg), and almost always for over 1.0 carat (200 mg), and are considered an important tool in guaranteeing that a GIA diamond is accurately represented to.
IGI Diamond History
IGI is the world's largest and most respected gem appraisal and grading institute. It is recognized for its expertise, and known for its exacting standards. IGI was established in 1975, making it one of the world's oldest gemological institutes in Antwerp. It was originally a small operation with just 3 gemologists. In the last 30 years, it has expanded to include nearly 500 gemologists and scientific technicians. The IGI provides over a million gem certifications a year. Clients include jewelers (both traditional and those who sell loose diamonds online), insurance companies, international law offices, certified public accounting companies, and private consumers. The requests have increased significantly in the last years. Twenty years ago only professional jewelers had any need or desire to get an IGI grading. But now consumers are buying loose diamonds, and have become more aware of the 4 C's and the need to get accurate and objective information. To keep up with the demand, the IGI holds several offices all over the world, in key cities like New York, Tokyo, Mumbai, Hong Kong, Bangkok, Dubai, Toronto, Los Angeles and Cavalese.
IGI Diamond Certification
Any diamond that is submitted to IGI is put through a rigorous grading process. An entire team of graduate gemologists is assigned. They use top-of-the-line technology to measure the diamond's 4 C's. To determine weight, the IGI specialists use an electronic balance. This machine can actually measure up to the ten-thousandth carat! Then the team rigorously examines each angle and facet of the stone, evaluating the stone's symmetry and polish. Does it reflect light efficiently? How precise are the cuts? Only then can they give a quantitative analysis on the diamond's brilliance, or how it delivers that eye-catching shine. The team must then put the stone under a very powerful microscope and loupe to check the diamond's internal quality, or clarity. They will be able to spot even the minutest imperfections, often missed by inexperienced jewelers (which is why a certification is crucial when purchasing any stone that claims to be flawless or near flawless). Color is checked by comparing the diamond to similar stones. The gemologists each submit their report, which must verify each other's information.
IGI Diamond Reports
The IGI actually issues three different types of reports. The Diamond Report authenticates a diamond by documenting its 4 C's. This is the standard report that is often displayed with the stone in the jewelry stores. For very large and valuable stones, the IGI can also include a very small version of the report in the actual container, which is sealed to prevent tampering. The IGI can also make an Identification Report. This is more visual, with a large photograph of the diamond (rather than the quantitative information provided in the Diamond Report). This normally tackles proportions and measurements, and is often used when the diamond has already been put into a jewelry setting. Lastly, the Appraisal Report is usually given to insurance companies, and provides a general estimate of what it would cost to replace the stone.
EGL Diamonds - European Gemological Laboratory (EGL)
EGL has been considered one of the key innovators in gem appraisal, having developed several methods of scrutinizing the quality of diamonds. It was the first lab to grade diamonds weighing less than one carat. It also introduced the "S13" designation for establishing clarity now accepted and used by the diamond industry and gemological laboratories around the world.
EGL Diamond Grading Process
A team of 8 experts, including 4 trained and experienced gemologists, looks at every diamond submitted to EGL. They then implement a series of tests. First, the diamond is weighed and measured, and its culet and girdle thickness measured with very precise instruments. Then it is placed in a specially lighted room (which has been scientifically calibrated for exact results). Here, the team looks at the stone's color, by comparing it to a set of master diamonds. At least 3 experts must agree on the color grade for the results to be official.
In order to check for clarity, the diamond is examined with a special zoom binocular microscope. The experts look at all of the diamond's facets, scrutinizing for blemishes and inclusions. These are then mapped on a diamond diagram also referred to as a diamond plot. The diamond is then tested for polish and symmetry, which are indications of the skill and craftsmanship of the cutter. The team checks proportions, and measures the brilliance of the stone. EGL also offers a service that can allow buyers to identify or embellish very precious stones. This is the Diamond Laser Script service.
Using high-precision instruments, EGL can inscribe the EGL certificate number on a diamond, along with key information like the weight, color and clarity grade. Clients can also write their name or personal messages (even "Happy Anniversary!"). It is very important to ask if a loose diamond has a certification before you buy it. If it does not have a certification, insist the diamond be sent to any of the 4 institutes listed above. If the jeweler refuses, this is a big warning sign that he may be trying to hide something. Certification is a standard practice among reputable diamond distributors.