AGS
The American Gem Society was established in 1934 by a select group of independent jewelers and also Robert M. Shipley, the founder of the Gemological Institue of America ( GIA ). AGS’s practice is to promote universally-accepted standards for grading diamonds, gemstones and metals.
Asscher
A fully made emerald cut with very large corners.
Blemish
There are several different types of blemishes, or flaws, that you might see on the surface of a diamond. Most diamond blemishes are a natural part of the gem while others occur either when the diamond is cut and polished or while you are wearing it. Surface blemishes may degrade diamond clarity and value, although most blemishes have little affect on a diamond’s appearance.
Brilliance
The effect that makes diamonds the most unique among all other gemstones. Brilliance is created when light enters through the table of the gemstone, reaches the pavilion facets, and is then reflected back out through the table. This is what makes a diamond sparkle to the eye.
Brilliant Cut
Designed for maximize brilliance, it is one of three types of faceting arrangements. Round diamonds, ovals, radiants, princesses, hearts, marquise, and pears all fall into this cut category. In a brilliant cut diamond all facets appear to radiate out from the center towards its outer edges. A standard brilliant round consists of a total of 58 facets: 1 table: 8 bezel facets, 8 star facets and 16 upper girdle facets on the crown: and 8 pavilion facets, 16 lower girdle facets, and usually a culet on the base.
Carat
A diamonds weight is measured in carats. The higher the carat (size) of a diamond the more valuable and rare it becomes. Its size “1″ carat is about 0.2 grams and a (1) carat is also equal to 100 points. For example a 50 point diamond written as(0.50) is the same as saying a one-half carat diamond.
Carbon Spots
When viewed under a microscope, included crystals that have a dark appearance rather than a white appearance are referred to as carbon spots. This term is often misused in the jewelry industry to describe the appearance of certain inclusions in a diamonds. Carbon spots, in most cases, are not visible with the naked eye and don not affect the brilliance of a diamond.
Clouds
When viewed under a microscope, the groupings of several tiny inclusions that appear to look like a soft transparent cloud are referred to as clouds. This inclusion cannot be seen with the naked eye and usually do not effect a diamonds clarity grade.
Crown
This is the upper part of a cut gemstone and is located above the girdle. The crown consists of a table facet surrounded by star or bezel facets.
Culet
This is the small facet that is polished parallel to the table, which would be otherwise referred to as the sharp point or ridge the ends the pavilion of a faceted diamond.
Depth
Measured in millimeters, depth is the distance from the culet to the table.
EGL
Originally part of the international network founded in Europe, EGL (Europe Gemological Laboratory), EGL-USA is one of the oldest independent gemological institutions around. EGL-USA focuses on gemstone certification and research. The first US lab was opened in the center of New York’s international diamond and jewelry district in the year 1977. As the company’s reputation grew so did its presence in the United States, now having offices in Los Angeles, Vancouver and Toronto.
Emerald Cut
This is a form of “step” cutting used in the diamond process. Its usually a rectangular shape but sometimes is square in which case it is a square emerald cut. It has rows of elongated facets on the crown and pavilion, parallel to the girdle, and with corner facets.
Facets
A flat, polished surface on a diamond or gemstone.
Feathers: When viewed under a microscope, the transparent or light white inclusions that have a feathery appearance to them are referred to as feathers. They are mostly caused by the tremendous stress that the diamond suffered while growing underground. Feathers begin and end within the diamonds surface, and sometimes begin inside the diamond and reach to the surface.
F
Abbreviation for, Flawless on the diamond color scale. Refers to the imperfections or inclusions in a diamond if any. This is one of the characteristics that make up a diamonds 4 C’s.
Fluorescence
This grading element is apparent when the diamond has a reaction to UV light. Fluorescence is graded from “None” to “Very Strong” with several grading shades between. Even though diamonds with fluorescence fall slightly less in price to diamonds without, this characteristic for a growing number of people seems to be a sought after novelty. Diamonds usually fluoresces blue although occasional stones may glow light red, green, orange or yellow.
Girdle: The outer edge of a fashioned diamond or stone. This is the part that is usually grasped by the setting or mounting.
GIA
The Gemological Institute of America, GIA, was founded by Mr. Robert M. Shipley in Los Angeles California in the year 1931. The Wichita jeweler devoted himself to gemology in Great Britain in the year 1928. Learning from the worlds experts, of that present day, Mr. Shipley returned to the United States influenced with a wealth of information from Europe’s scholars and institutions.
Hope Diamond
The Hope Diamond is a 44.5 Carat diamond presently at the Smithsonian. It was submitted by Harry Winston in 1958. The Diamond acquired its name in 1762, when it was acquired by a member of the banking family Hope & Co. The diamond has a unique sapphire (dark blue) color. The stone is one of a kind; experts have yet to determine its true value.The diamond it seems has carried with it a history, in its past of several misfortunes that some may call coincidence, for others rumors of a curse. The Hope diamonds was first owned by Marie Antoinette, who as fortune would have it was beheaded. Even earlier the cutter of the diamond died of a grief and shame, after his son had stolen the diamond. As a result the son soon died shortly after by committing suicide. The person that found the diamond among his “remains” died the very next day. As the hope diamond has gone over the years the events seem to get stranger. Could this diamond be cursed to all who owns it? The Hope diamond later found its way in the possession of the jewelry Cartier, who sold the diamond to Mrs. Evelyn Walsh who claims that anything with bad luck gave the opposite effect on her. Still yet, soon after her possession of it, several members of her immediate family died (brother, son and daughter). After several years it was presented to the Smithsonian, where it now is available for anyone to see its beauty without the stigma of its cure.
Inclusion
A clarity characteristic found within a diamond that is created while the gem was forming in the earth.
IF
Abbreviation for, Internally Flawless. Refers to the imperfections or inclusions in a diamond, if any. This is one of the characteristics that make up a diamonds 4 C’s.
Jewelers’ Vigilance Committee
This group is a non-profit organization that was founded in 1912. Its purpose was and is to advance ethical practices in the jewelry trade. This organization has representatives of every branch of the jewelry industry.
Karat
Karat is the term used for measuring the gold purity. Be careful not to confuse “Karat” (KT) used to measure gold purity with the term “Carat” which is used to measure a gem stone�s weight. One karat is equivalent to 1/24th the total purity of gold itself.
Loupe (loop)
The small magnifying glass used to inspect diamonds is popularly know as a loop. A loupe may contain a single lens or a system of lens which range from 2 to 20 power or more.
Marquise Cut
A style of diamond cutting in which the girdle outline is boat shaped, or oval like that of an “American football.”
Mohs Scale
the most well know scale to measures relative hardness of minerals is know as the Mohs scales.
Natural
The original surface of a rough diamond that is sometimes left by the cutter on a fashioned stone, usually on the girdle Some consider naturals to be blemishes on a stone while others just dismiss this as not being a blemish. The school of though is as long as the girdle outline is not flattened or extends beyond the width of a medium girdle this is a perfectly acceptable.
Oval Cut
This is a brilliant cut in which the girdle outline is elliptical.
Pavilion
The portion of a faceted diamond or gemstone located below the girdle.
Pave’
A Pave’ setting is created when the surface of ring or piece of jewelry is covered with tiny diamonds. Tiny diamonds are inserted in small holes that have been drilled out of the ring shank. The diamonds of all of relatively the same size and are placed in rows across the surface of the ring. This is done with great care so as to fill as much space as possible without touching each other. With an exercise as tedious as this the better cut diamonds used the better the overall appearance of the completed piece. Each tiny diamond, weighing just a few points, is fully cut with 58 facets. After placing each diamond is complete, tiny bits of metal from the surface of the shank are pushed over the edge of the diamond, forming tiny beads to hold the stone in place. If a section of the ring is Pav�-set, with certain areas tapering to a point, the diamonds should diminish in size as the Pav� area narrows. This requires the most precise selection of diamonds.
Pear shaped cut
This is a variation of the brilliant cut diamond. Usually having 58 facets, with a pear shaped girdle outline. They often have 56 facets when the pavilion facets at the head and tail are eliminated.
Polish
The smoothness of each facet after it has been polished is graded on a scale from fair (F) to excellent (EX). Polish marks cannot be seen by the unaided eye and have a subtle if not minute effect to the brilliance of a stone.
Round Cut: See definition for Brilliant Cut.
SI
Abbreviation for, slightly included. Refers to the imperfections or inclusions in a diamond.
Symmetry
This is the alignment of the facets with each other. If a stone�s facet varies significantly with unequal measurements, this will cause loss of light and loss of brilliance. Contributors to this will be consistency in the girdle around a stone and unequal facets.
Table
The large facet that caps the crown of a faceted diamond or gemstone.
Table Percentage
The size of the table of a faceted diamond, expressed as a percentage of the stone’s diameter, is a dimension used in proportion analysis.
VS
Abbreviation for, very slightly included. Refers to the imperfections or inclusions in a diamond.
VVS
Abbreviation for, very very slightly included. Refers to the imperfections or inclusions in a diamond.
All of the Definitions for the Diamond Dictionary Came from HERE.
