Here are some common words used in the Diamond Industry and on this web site

4Cs Diamonds are graded and priced according to what is universally referred to as the "4C's". They are Cut, Color, Clarity and Carat Weight. Here is an explanation of each of the 4Cs:

Appraisal
A valuation of property by the estimate of an authorized person. With diamonds the appraisal is a written estimate of the approximate retail
replacement value of diamond jewelry, which may be used for insurance coverage or other purposes. It is not the same as a grading report, which evaluates a diamond's characteristics (such as cut, clarity, carat, symmetry, etc.) only.

Blemish
A scratch or abrasion on the surface of a diamond. Provided they do not interfere with the symmetry of the stone and do not interfere with light in the stone they are not considered important.

Brilliance
brilliance is the white light that is reflected through the top of a diamond. This can be increase by the diamond being cut to the correct
proportions to take advantage of the reflection of light from the facets to the brilliance.

Brilliant Cut
A Brilliant Cut, sometimes called the American Brilliant, is a 58-facet round diamond, This shape and faceting arrangement is designed for maximum brilliance, sparkle and beauty and is perhaps the most popular shape.

Carat
Perhaps everyone know the term carat. The basic unit of weight for a diamond. A carat is equal to 200 milligrams, or one-fifth of a gram. It is said that the word is derived from the word carob. In early India the carob bean was used for measuring the weight of gems as every carob seed weighs exactly the same.

Clarity
Clarity is the term given to indicate the purity of a diamond. Most diamonds have minute imperfections and the clarity is the way of grading the purity depending on the number of imperfections the diamond has or does not have.

Cloud
A cluster of very small inclusions inside a diamond that give a cloud effect. Tiny clouds will not interfere with the flow of light, but large or numerous clouds can affect brilliance.

Color
Diamonds are traditionally thought of as white or clear. But diamonds in fact do have color and this can be graded.

Crown
The crown is the top section of a diamond, above its widest point, or girdle, that comprises the table, and the star-, bezel- and upper-girdle
facets.

Culet
A facet on the very bottom of a diamond. It is best to have a small or medium culet. A large culet will make it look like there is a hole in the
bottom of the stone due to leakage of light. Absence of a culet makes the point of the diamond more easily damaged or chipped.

Cut
This describes the shape of the diamond. There are basically eight cuts of diamond.

Some of the most popular diamond cuts include Heart, Emerald, Marquise (Oval with pointed ends), Oval, Pear, and Princess with the Round Brilliant (R/B) probably being the most popular.

Depth %
The height of a diamond (measured from the culet to the table) divided by the width of the diamond. The depth % is critical to creating brilliance and fire in a diamond. A depth % that is too low or too high will cause light to leak out of the stone, causing the diamond to lose sparkle.

Depth
The height of a diamond (measured from the culet at the very bottom to the large table facet on the top).

Diamond
The simplest of all the gemstones consisting of pure crystallized carbon. A diamond crystallizes under enormous pressure deep beneath the earth's
surface Diamonds can be from 1 to 3 billion years old--more than two-thirds the age of the Earth itself. Diamond is also the hardest substance known to man. In fact, it can only be cut and polished by another diamond. Despite its hardness, however, it is not indestructible. If a diamond is struck at the right angle, it can chip or break.

Eye-clean
A diamond that has no inclusions visible to the naked eye -- flawless to the naked eye. This is normally true of all diamonds with a grade of about SI-1 or higher on the clarity scale.

Facet
The polished flat surfaces on a diamond. For example, a round brilliant diamond has 58 facets when counting the culet.

Fair Cut
Diamonds cut to less than perfect proportions. They have been cut to maximize the weight of the stone instead of enhancing the brilliance and sacrifice fire and brilliance. The less expensive stones may have good and very good cuts but will not have the same brilliance and fire that people would expect from a diamond.

Fire
Fire is the colored light that is reflected from inside the diamond. Colored light reflected from within a diamond. As in a prism light entering a diamond is divided up into the spectrum. The better quality diamond with better proportions the better the 'fire' of the diamond. This is called "refraction" or "dispersion" in the diamond trade.

Fluorescence
A glow, usually of a bluish color, which emanates from certain diamonds when exposed to ultraviolet light. Two thirds of all diamonds fluoresce to some degree but how they do so depends very much on the type of ultra violet light they are under.

Girdle
this is the narrow band around the outer circumference of a diamond. This is where a jewelry setting holds the diamond in a ring.

Good Cut
Diamonds cut with acceptable, but not perfect, proportions. They generally have very good brilliance and fire and make excellent jewelry.

Ice
A colloquial word for diamonds, much favored by Hollywood in movies about gangsters.

Ideal Cut diamonds are usually more expensive than all other cut grades. This is due to three major factors: 1) extra time and skill are required to cut to such precision; 2) they are in great demand, and perhaps most importantly, 3) more of the original rough diamond must be sacrificed to achieve ideal proportions. Ideal Cut diamonds are also round diamonds that are perfectly proportioned (having depth percentages and table percentages that some people feel produce a "perfect" balance of fire and brilliance). They almost always have the highest grades on polish and symmetry as well, indicating the great care taken in the overall fashioning of the stone. These diamonds have had the finest craftsmanship to maximize the beauty of the diamond.

Inclusion
An impurity within a diamond, such as a spot or irregularity in the crystal structure of the stone. These can include a cloud, a fracture, another diamond inside the bigger one, liquid, etc. Inclusions can either be visible with the naked eye (usually SI-3 clarity and below) or visible only under magnification. Fewer inclusions means a finer clarity grade, increased rarity, and increased value.

Kimberlite
Kimberlite is a mica peridotite and a source of rich deposits of diamonds. The deposits occurring at Kimberley, South Africa were the first recognized and the source of the name. The Kimberly diamonds were originally found in decomposed kimberlite which was colored yellow by limonite, and so was called "yellow ground." Deeper workings encountered less altered rock, undecomposed kimberlite, which miners call "blue ground.

Loupe
A loupe is a small magnifying glass used to view gemstones. Usually 10x, or ten-power, magnification. The FTC requires all diamond grading be done under 10-power magnification; any flaws not detected under this magnification are considered to be non-existent.

Make
Make describes the quality of the finish and proportions of a diamond. A good make will have proportions that maximize brilliance and fire. A poor make will decrease sparkle and fire due to the loss of light as it travels through the stone. The cutter is responsible for the make of a diamond as he is the one that cuts it to achieve the maximum brilliance and fire.

Mica
Any of a group of chemically and physically related aluminum silicate minerals, common in igneous and metamorphic rocks, characteristically splitting into flexible sheets used in insulation and electrical equipment.

Mohs Scale
The Mohs scale is a table of relative hardness that ranks a mineral's strength and durability on a scale from 1 to 10, with 1 being talc and 10 being diamond. Developed over 100 years ago by Frederic Mohs

Moissanite
Moissanite is silicon carbide and is manufactured in a laboratory. it is virtually indistinguishable from diamonds and takes a real expert with special equipment to be able to tell the difference

Pavilion
This is the bottom half of a diamond, from the lower girdle to the culet at the bottom tip. The pavilion should neither is too deep or too shallow or else light will leak out and the diamond will lose fire and brilliance.

Peridotite
Any of a group of igneous rocks having a granite like texture.

Point
A measure of diamond weight. One point equals 1/100th of a carat. A diamond that weighs 0.50 carat is said to weigh 50 points.

Polish
A grade given to the external finish of a stone. The polish grades from poor to excellent. Good polish is crucial for maximum brilliance of a diamond, but it takes a trained eye to distinguish between polish grades.

Poor Cut
Poorly cut diamonds with proportions and finish that make them look relatively lifeless to the eye. Such stones are ok for industry but not for jewelry.

Sparkle
the 'sparkle' of a diamond is the combination of fire and brilliance. The light that reflects out of a diamond as it moves. Sometimes called"scintillation" by older dealers.

Stones
A word for diamonds and other precious gems.

Symmetry
A diamond should by symmetrical. Symmetry is the grade used to describe the uniformity of the cut of the diamond. This can =range from excellent down to poor. The unsymmetrical a diamond is the poorer will be the quality of light through the stone.

Table
the top or large flat face of the diamond is called the table. It should be in proportion to the rest of the diamond to gain the best fire and brilliance.

Tourngat
A region of northern Quebec.

Very Good Cut
Diamonds cut to fit very strict requirements for depth percentage and table percentage. These outstanding proportions maximize fire and brilliance in the diamond.

Weight
the weight of a diamond is measured in carats.A carat is .2 grams. A gram of diamond would be a massive 5 carats. Very large in diamond terms although the actual diamond is physically small.

Wholesale
Wholesale prices are listed PER CARAT to show this price difference. For instance, a 1/2-carat round brilliant diamond of G/VS2 quality may sell for $3,600 per carat ($1,800 for the stone), whereas a 1-carat stone of the same quality would likely cost $6,300 per carat ($6,300 for the stone) because it is twice the size and more rare.

Zirconia
Also known as Cubic Zirconia, this is a substance often used as a substitute to genuine diamonds. It is a carborundum substance and esily told from diamonds.