Diamond Education
Diamond Buyers Guide

Top

It is very important that you educate yourself about diamonds before you purchase your "perfect diamond". It is also intriguing to find out all the background history of diamonds. All the information you need is right here. Learn the different shapes of diamonds, the colors, including Fancy colored diamonds, these beautiful but rare gemstone are fascinating. Learning the 4C's before you shop for your diamond will give you the knowledge you need to pick out your perfect diamond". Learning detailed information on all the diamond shapes available can you give you a more informed choice. Learning all about diamond clarity and diamond color will help you better understand the diamond grading certificate. A diamond is measured in Carat Weight.

Depending on the type of Diamond Cut the diamond has will show in the brilliance and the shine of the diamond. Other important factors are Fluorescence, Polish and Symmetry.

Wonder what all the diamond shapes look like? Just click the appropriate shape to go directly to the specific part of the page.

Emerald Cut Diamond Heart Shaped Diamond Marquise Cut Diamond
Oval Cut Diamond Pear Shaped Diamond Princess Cut Diamond
Radiant Cut Diamond

The 4 C's

Carat Weight

The weight or size of a diamond is measured in carats. A carat is 0.2 grams and there are 100 points (or 200 milligrams) per carat. With an accuracy of 1/100,000 ct, the scales provide a highly precise diamond weight and this weight is specified on the Diamond Report to two decimal points.


Carat	0.05	0.10	0.20	0.25	0.30	0.40	0.50	0.70
Øm/ m	2.5	3.0	3.8	4.1	4.5	4.8	5.2	5.8
h m/ m	1.5	1.8	2.3	2.5	2.7	3.0	3.1	3.5

Carat	0.90	1.00	1.25	1.50	1.75	2.00	2.50	3.00
Øm/ m	6.3	6.5	6.9	7.4	7.8	8.2	8.8	9.4
h m/ m	3.8	3.9	4.3	4.5	4.7	4.9	5.3	5.6

Diamond Clarity:

In order to grade the clarity of a diamond, it is necessary to observe the number and nature of any internal characteristics in the stone as well as their size and position. This analysis is carried out using the scope and a loupe 10x under the experienced eye of laboratory gemologists. A diamond is said to be "Internally Flawless" when it presents no internal defects under 10x magnification.


Internally Flawless	Very Very Slightly included	Very Slightly included
Free from internal blemishes visible under 10x magnification (small external details tolerated).	Inclusions and/or external blemishes very difficult to locate under 10x magnification.	Inclusions and external blemishes difficult to locate under 10x magnification.


Slightly included	Imperfect	Imperfect	Imperfect
Inclusions and external blemishes easy to locate under 10x magnification.	Inclusions and external blemishes hard to locate with naked eye.	Inclusions and external blemishes easy to locate with naked eye.	Heavy inclusions located with naked eye.

Diamond Color:

Most diamonds of gem quality vary in shade from colorless to yellow. To determine the correct color, all submitted diamonds are compared to an internationally accepted master set of stones, the color of which ranges from D, or colorless (the most sought-after) to Z, the yellowiest. Other colors occur in diamonds such as brown, orange, pink, blue, etc. The most intense of these shades are determined as "Fancy" colors and mentioned on the Diamond Report.

			CIBJO	IDC
	Colorless	D	Blanc Exceptionnel	Exceptional White+
		E		Exceptional White
		F	Extra Blanc	Rare White+
	Near Colorless	G		Rare White
		H	Blanc	White
		I	Blanc Nuancé	Slightly Tinted White
		J
	Faint Yellow	K	Blanc Légèrement Teinté	Tinted White
		L
		M	Teinté	Tinted
						Very Light Yellow	N
O
P
Q
R
	Light Yellow	S
					T
		Yellow			U
	V

Diamond Cut:

Cut

How a diamond has been cut, polished, and to what proportions and symmetry, are of utmost importance since these factors determine the life, brilliance and dispersion of the diamond. If these cutting factors fall below standard, the appearance of the diamond will be adversely affected.

Diamond Culet:

A diamond's culet is the point on the bottom of a diamond's pavilion. A diamond's culet may be pointed or it may be blunted with a small facet. The culet facet can vary in size. This culet's size determines the grade that the culet is assigned.

Depth Percentage

This is the main factor in determining the life and brilliance of the diamond (shallow or deep stones will not look good). The height of the stone is divided by the diameter in rounds or by the width in all other shapes. Ideal round diamonds should have a depth of 59%-62.5%. This is a relatively narrow range that has been proven to produce the best "brilliance" from the diamond. Brilliance is the light that is reflected back to the viewers eye. Flat and heavy cut diamonds will loose light through the bottom and sides of the diamond thus reflecting less light to the viewers eye.

Table Percentage

The table is the big facet on the top part of the diamond. Very big or very small tables will harm the stone's beauty. Only round diamonds have a standard for table size. Cut quality in all other shapes is more dependent on depth, girdle and length to width ratio.
In round diamonds for a diamond to be recognized as an "Ideal cut" the table must be relatively small. It must fall between 53% and 57%. Calculations have shown that tables in this range produce the greatest "fire" effect in the diamond. "Fire" is the reflection of light back to the viewer’s eye that produces the rainbow colors that are seen.

Diamond Symmetry

Symmetry is an important element of diamond finish. Symmetry refers to the exactness of the shape and arrangement of facets. This includes naturals, misshapen facets and extra facets, off center culets and tables, wavy and out of round girdles, misalignment of crown and pavilion facets.

To the unaided eye, finish features usually have little effect on appearance; they are like pinpoint inclusions. The importance of symmetry is less important in diamonds that have lower clarity grades. Symmetry is more important in diamonds that have very high clarity grades.

When selecting your diamond, choose one of the following symmetry grades:

Excellent
Very Good
Good

Symmetry is listed on the certified diamond grading report. Few diamonds are available with Excellent or Very Good symmetry. Diamonds with a symmetry grade of Good offer exceptional beauty and are purchased most frequently. United Diamonds has not to this date received a diamond returned due to a customer dissatisfaction with the symmetry grade of Good. Although symmetry is important, it is best to place more emphasis on diamond depth percentage, table percentage, crown and pavilion height as well as color, clarity and weight. Diamonds with fair to extremely poor symmetry should be avoided. Listed below is a list of abbreviations and brief descriptions of symmetry grades that are used by GIA, EGL, and IGI.

EX or E - Excellent, Flawless at 10 power
VG or VGD -Very Good, Extremely difficult to locate under 10 power
GD, GO, G - Good, Very difficult to see under 10 power
F, FR, FA - Fair, Noticeable under 10 power
PR, PO, P - Poor, Easy to see under 10X / Visible to unaided eye
VP, VE, - Very Poor, Relatively easy to see with the unaided eye
EX or EP - Extremely Poor, Obvious to see with unaided eye

Diamond Polish

Polish is determined by the quality of finish given to the diamond. Tiny blemishes, scratches or surface graining can all lower a diamonds polish grade. Polish influences how well light is able to pass through a diamond and is very important to a diamond's brilliance. It is necessary to select a diamond that is laboratory certified with good, very good or excellent polish. Diamonds that have poor to extremely poor polish are less brilliant because they have microscopic polish lines that blur the surface of the diamond. These polish lines reduce the amount of light that enters or exits a diamond. All polish grades are determined with aid of x 10 magnifications.

EX or E - Excellent, Flawless at 10 power
VG or VGD - Very Good, Extremely difficult to locate under 10 power
GD, GO, G - Good, Very difficult to see under 10 power
F, FR, FA - Fair, Noticeable under 10 power
PR, PO, P - Poor, Easy to see under 10X / Visible to unaided eye
VP, VE, - Very Poor, Relatively easy to see with the unaided eye
EX or EP - Extremely Poor, Obvious to see with unaided eye

Diamond Diagram

Diamond Girdle

The girdle is the outer edge of a diamond. This is the part of the diamond that connects the bottom and top, and reveals the stone's quality of cut. The grade of diamonds girdle is determined by the appearance of the girdle at its thinnest point and thickest point. A girdle could be Thin, Medium, Slightly thick or any combination of the three, such as "medium to slightly thick". Extremely thick girdles are signs of bad cutting and should be bought cheaper. Extremely thin girdles may be prone to damage and should be avoided if possible. A diamond's girdle can be faceted, polished smooth, or have a slightly granular appearance. A faceted girdle does not improve a diamonds grade.

Fluorescence:

Strongly fluorescent diamonds with yellowish body color have the appearance of better, whiter color in sunlight, a source of ultraviolet light.

These lower-color diamonds with powerful fluorescence often command a premium.

Fluorescence in some degree is common in a great percentage of diamonds. Fluorescence is a form of illumination that is created when a diamond is exposed to low or high wave ultraviolet radiation. Faint or medium fluorescence will rarely affect a diamond's appearance. Usually fluorescence is unnoticed by the human eye in ordinary light. Fluorescence can cause a diamond to appear less clear or slightly hazy if the diamond exhibits very strong or extreme fluorescence. Diamonds that possess strong fluorescence in color grades lower than the color grade of H will often face up approximately one color grade better than a non-fluorescent diamond. Strong fluorescence can actually improve the appearance of diamonds that possess traces of color. Diamonds that possess strong fluorescence in colorless to very near colorless grades D through G sometime exhibit a noticeable luminescence which can give the diamond a hazy appearance.

Diamond Shapes

The most common diamond shapes are round, emerald, princess, radiant, oval, pear, marquise and heart. Because round cut diamonds are the only shape that can achieve an ideal cut, they are the most brilliant of the diamond shapes. Fancy shaped diamonds adhere to different proportion guidelines and thus refract light in different ways.

Marquise Cut Diamond

The Marquise Cut takes its name from a legend relating to the Marquise of Pompadour. According to the legend, the Sun King desired a stone to be polished into the shape of the mouth of the Marquise. It is generally agreed that a length-to-width ratio between 1.75:1 to 2:1 is most pleasing. As with other fancy shapes, the consumer's individual taste constitutes an element of the evaluation as well. The typical marquise diamond contains 56 facets.

Princess Cut Diamond
The Princess Cut Diamond is a brilliant style shape with sharp, uncut corners. It is typically cut square rather as a rectangle. Brilliant style refers to vertical direction crown and pavilion facets instead of step style horizontal facets. A princess Cut Diamond generally has 76 facets, giving it more brilliance and fire than the round brilliant. The Princess Cut diamond is fast becoming one of the most popular cuts in the United States

Radiant Cut Diamond
The Radiant Cut Diamond is a straight-edged rectangular or square stone with cut corners. The radiant cut diamond has 62-70 facets. Radiant diamonds are principally used for important center stones primarily for rings but also for pendant. They are rarely used for earrings or as side stones because they are hard to calibrate and match. To get matched pairs you may have to sort through a hundred stones are re-cut to calibrate.

Emerald Cut Diamonds
An emerald cut diamond shape is usually rectangular. The flat planes of the outside edges allow for a variety of side stones shapes. Typical pairings would be two or three side baguettes, two half-moons, and other smaller emeralds, but not trillions ,as their sparkle makes the center emerald cut look flat. The length-to-width ratio should be between 1.5:1 to 1.75:1.

Pear Shaped Diamond
The pear shaped brilliant diamond is based upon the traditional configuration of the round brilliant diamond. More than other fancy shapes, length-to-width ratio is a matter of taste when it comes to pear shaped diamonds. Because pears may be used for engagement rings, suites in necklaces, dangles in earrings, and integral parts of custom designs, a wide variety of shapes is considered desirable. The typical pear shaped diamond will contain 58 facets.

Oval Cut Diamond
The oval cut diamond is based upon the traditional configuration of the round brilliant diamond and that's why its technical name is oval modified brilliant diamond. The oval was invented by Lazare Kaplan in the early 1960s. A length-to-width ratio of 1.5:1 is almost universally considered a pleasing shape for oval diamonds, with any variation beyond 1.4:1 or 1.6:1 beginning to be noticeable and become an aesthetic issue. However as with all fancies, a certain degree of individual taste is always factored into the desirability of a particular diamond's shape. Fifty-six facets are typical for oval brilliant diamonds. Over the last year or two ovals have become very popular as center diamonds for engagement rings

Heart Shaped Diamond
Romantic perfection for the special occasions. The perfect stone for the special occasion requirements. The Heart shaped brilliant is the hit item on Valentines day. Usually the width will be 10% wider than the head-to-point length

Diamond Jewelry Care

Because diamond is the hardest known substance you must be careful when storing your diamond jewelry, as it can scratch other gemstones and metals. Store diamond jewelry separately in a cloth pouch.

Avoid salt water and harsh chemicals and detergents when wearing your diamond jewelry. As much as possible try to keep your diamonds free of perspiration, dirt, cosmetics, and hair spray. (You can bathe while wearing gold without causing harm. Ordinary soap, however, can dull it).

Always put on jewelry after you have applied cosmetics, perfumes, after-shaves, hairsprays, etc

Remove all jewelry before engaging in such activities as sports, housework or yard work where jewelry is prone to impacts and/or chemicals.

Check for loose gems and clasps before each wear.

Pearl and bead necklaces should be restrung at least every two years, annually if you wear them frequently.

Wipe your jewelry off before each wear

Always insure your jewelry.

Clean your jewelry at your trusted local jeweler every six months. Use this opportunity to ensure that your gemstones are secure.

Diamond Diagram

Girdle: the portion that encircles the stone at the boundary between the crown and the pavilion

Crown: portion of the stone located above the girdle

Table: flat facet on top of the crown

Pavilion: the inclined area between the girdle and the culet

Culet: point where the pavilion facets meet