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Most cuts for Diamonds
Emerald Cut Diamonds Marquise Cut Diamonds Oval Cut Diamonds Pear Cut Diamonds Natural Fancy Colored Diamonds
Princess Cut Diamonds Round Brilliant Diamonds Triangle Cut Diamonds
Heart Shaped Diamonds
The Four Cs of Faceted Diamonds
The four Cs provide a standard for evaluating Diamonds.
The first step in helping our customers choose
diamonds is to clearly convey the meaning
and importance of the Four Cs; color, cut, clarity, carat weight.
Many customers are often not well informed. Here we offer this information to
help you understand the importance of the Four Cs.
Diamonds can cover the entire spectrum of colors. The majority range from a perceptible yellow or brownish tint up to the very rare diamonds described as colorless. Colorless diamonds are the most desirable since they allow the most refraction of light (sparkle). Off white diamonds absorb light, inhibiting brilliance. You can best observe diamond color by placing the stone table side up on a flat white surface or grading trough, and examining it from different angles. Next, place it table-side down with the culet facing you, and examine it through the pavilion facets.
Cut has the greatest influence on the diamonds fire and brilliance. A round, brilliant-cut diamond has 28 facets. When well proportioned, this shape best shows the stones brilliance because it allows the most light to be refracted back to the eye of the observer. Stones that appear lifeless or stones that appear dark in the center are poorly cut. When the angle relationship between the crown and pavilion facets is correct, rays of light entering the diamond strike the rear facets at an angle greater than the critical angle. (24.5 degrees for diamond), and reflect back to the eye of the observer. If the stone is cut too deeply the light strikes the rear facets at an angle less than the critical angle and the light is lost through the sides of the diamond. If the diamond is cut too shallow, the light passes through the diamond without being reflected back. (no sparkle).
Most diamonds contain minute traces of non-crystallized carbon in internal stress factors. Called inclusions, most of these are not apparent to the naked eye but can be seen under magnification. Perfect clarity means that no inclusions are discernible when the diamond is examined under a 10x magnification lens. Inclusions greatly effect the beauty and value of a diamond because they absorb the light rather than allowing it to be reflected back through the front side of the stone. How much they reduce the value of a diamond depends on their size, number and position throughout the stone. An inclusion in the center of the diamond beneath the table is more visible than one near the edge. The inclusion may also be mirrored many times by adjoining facets.
The term "CARAT" comes from the ancient practice of weighing diamonds against the seeds of a carob tree. The system was eventually standardized, and one carat was fixed at 0.2 grams. One carat is divided into 100 points, so a quarter-carat diamond is 25 points or 0.25 carat. Although carat is a unite of weight, not size, the carat weight of a diamond has come to refer to particular sizes. If properly cut, diamonds of the same weight should be about the same size. These sizes do not apply to other gems, however, because their specific gravity's differ from a diamond.
One must be very careful when buying diamonds,
many diamond brokers have
no formal gemological training or the proper gem testing equipment to "Accurately"
evaluate diamonds. The job of diamond evaluation should only be performed
by a certified Graduate Gemologist who has many years experience in this field!
G.I.A COLOR SCALE
G.I.A CLARITY SCALE
|No blemishes or inclusions when viewed under 10X magnification.|
|No inclusions and only insignificant surface blemishes under 10X magnification.|
|VVS1 and VVS2:
Very very slight inclusions
|Minute inclusions that are difficult to see under 10X magnification.|
|VS1 and VS2:
Very slight inclusions
|Minor inclusions ranging form difficult to somewhat easy to see under 10X magnification.|
|SI1 and SI2:
|Noticeable inclusions that are easy to see under 10X magnification, although appear clean to the naked eye.|
|I1, I2 and I3:
|Obvious inclusions that are usually visible to the naked eye while stone is viewed face up.|
What is Diamond?
Diamond is Carbon
It may seem surprising that diamond is simply carbon, just like charcoal or graphite. In fact carbon has at least two other rare, and only recently discovered forms, or allotropes, known as fullerenes.
The difference is caused by the different types of bonding between adjacent
atoms to form different types of crystalline structure.
In diamond, each carbon atom is bonded to four other carbon atoms in a tetrahedral structure, like a pyramid. Each link or bond is the same length, and the tetrahedral formation is therefore completely regular. It is the strength and regularity of this bonding which makes diamond very hard, non-volatile and resistant to chemical attack.
Theoretically a perfect diamond crystal could be composed of one giant molecule of carbon.
Carbon is a non-metallic element with the atomic number of 6, and an
atomic Weight of 12. In combination with oxygen and hydrogen it is contained
by all living objects. In the form of graphite it appears black or dark
gray, opaque, and is very soft, whereas in the form of diamond is it clear,
colourless, and extremely hard. In fact diamond is the hardest known naturally
Carbon has a density of about 2.3 and diamond about 3.5.
9 Corundum 667
8 Topaz 304
7 Quartz 178
6 Feldspar 147
5 Apatite 137
4 Fluorspar 64
3 Calcite 53
2 Gypsum 12
1 Talc 3
There are many different aspects of materials which could be considered
as a measure of hardness. Hardness can mean resistance to scratching, indentation,
bending, breaking, abrasion, cleavage, or fracture. It is easy to confuse
durability or toughness with hardness.
A very simple example is to consider a glass ball and a rubber ball. Glass is harder than rubber, but rubber is more durable. Try bouncing both on a hard floor, the glass ball will shatter, whereas the rubber ball will bounce.
The aspect of hardness which is measured by Moh's test is the scratchability of a mineral.
Other scales of hardness include Brinell's and Vicker's.
The hardness of each mineral relative to the others varies according to which test is performed, and also hardness can vary according to the grain direction, or crystallographic orientation, of the specimen. We have given typical Brinell hardness figures for each of the minerals in the table. Diamond's hardness cannot be measured on the Brinell scale, because a diamond indenter is used for the test itself, but it is many times harder than corundum.
Sapphire and ruby are the well known varieties of corundum.
Amethyst, citrine, rock crystal, and cairngorm are all varieties of quartz.
Generally, high scratch resistance is desirable for gemstones, and a
Moh's hardness of 7 or higher is important. The principal reason is that
a common cause of abrasion is sand, which is silica grit (quartz), and
is commonly present in dust. Stones which are softer than quartz are not
suitable for everyday use as facetted jewellery gemstones, particularly
in rings, although many are beautiful and attractive.
Some gems, such as pearls, coral, turquoise, lapis lazuli, amber, and opal are quite soft, but are usually polished into cabochons or beads, rather than facetted, and therefore do not show scratches so easily. All these gemstones have been successfully used in jewellery for many centuries.
ABOUT THE CUT
This determines the "sparkle" of your diamond by reflecting light through a complex prism of angular cuts. There is an industry standard "ideal cut," but simply looking over your stone should be enough: if it sparkles, it's a good cut. Dull diamonds are often cut too deep or too shallow.
Clarity refers to the absence of inclusions (imperfections) in the stone.
FL / IF Flawless or Internally Flawless.
VVS1 / VVS2 Very, Very Small Inclusions. Requires 70X magnification to clearly see inclusions.
VS1 / VS2 Very Small Inclusions. Requires 30X magnification to clearly see inclusions.
SI1 / SI2 / SI3 Small Inclusions. Requires 10X magnification to clearly see inclusions.
I1 / I2 / I3 Imperfect-Eye-Visible Inclusions
When you buy a diamond logically, you can avoid needless
expense. The difference between finding an inclusion in a diamond at 70X
magnification and one at 10X magnification is absolutely nothing to the
naked eye. However, this difference is likely to double or perhaps triple
the price of your stone. Since diamonds are marketed to be a direct reflection
of your love ... young couples are often persuaded to purchase a stone
that is beyond their means. Private Diamonds has the inventory to accomodate
all clarity demands, but we will never push a VVS1 when an SI1 looks the
same without the aid of a microscope.
CLARITY GRADING SCALES COMPARISON
Color defines brilliance or purity of the stone's hue. An absence of color is considered the purest, and most expensive.
Color is often seen differently depending on other factors.
For instance: by using a platinum setting , your diamond will look more
pure by a factor of 2 or 3 shades. Before you buy the purest stone, consider
where it will end up - you probably won't need the most expensive color
to get the best look.
COLOR GRADING SCALES COMPARISON
VERY LIGHT YELLOW
VERY LIGHT BROWN
N Light Champange
R Light Champange
W Medium Champange C3
FANCY BROWN Dark Champange
FANCY INTENSE YELLOW
FANCY INTENSE BROWN Fancy Cognac C7
Frequently Used Terms
All deposites laid down on land by the process of erosion
Same as Ideal cut
A monetary evaluation usually for insurance or estate purposes. An insurance appraisal is based on an estimate of the retail replacement value. An estate appraisal is an estimated realization from a quick sale.
A style of step cutting for a small rectangular stone. May also be tapered at one end.
If, during the cutting process, the girdle is rounded up too quickly, tiny, numerous, hairlike fractures extending into the stone will result. The surface of the girdle will lack the waxy luster and smoothness of a finely rounded diamond. It will appear fuzzy.
The small part of the top sloping surface just above the girdle.
The eight large facets on the crown whose upper points join the table and lower points the girdle
Surface imperfection. e.g. nick, knot, scratch, minor cavity or poor polish. An extra facet or a natural on the girdle are also considered blemishes.
The color of the diamond observed under diffused light against a colorless background.
Industrial quality diamonds
Brilliant cut (round)
The most common cut of diamond consisting of 58 facets.
A fancy yellow, greenish-yellow or orangy stone.
A term used in the trade to refer to any black appearing imperfection in a diamond. May be graphite or other dark mineral or even dark reflections from cleavages or included transparent crystals.
Term used for a small single cut diamond.
A curved break on a diamond's surface.
Generally the most damaging type of imperfection affecting durability as well as beauty. It is a break that usually extends to the surface although sometimes they will extand a short distance from an inclusion.
A group of tiny white inclusions that together give a cottony or cloudy appearance.
Devoid of body color.
the part of the diamond above the girdle.
The tiny facet at the lower tip of a diamond.
A square cut with rounded corners. An older form of the brilliant cut.
The property of diamonds to seperate white light into spectral colors.
A form of step cut. usually rectangular but may be square. the number of steps can vary. Will emphasize color.
The plane, polished surface placed on a diamond.
A cleavage or fracture resembeling the shape of a feather.
Flashes of the spectral colors as a result of dispersion.
A diamond whose pavilion is very shallow, producing a glassey stone with poor brilliance.
A general term used to refer to any imperfection in a diamond.
The property of changing one type of radiation to another. For example: UV rays from natural light excite the atoms in certian diamonds causing them to emit visible light (be lumimescent) .
When fluorescence causes a diamond to change color when exposed to two different kinds of light. A yellow stone (under incandescent light) may appear bluish under daylight.
A term for a diamond having 58 facets, consisting of 32 and a table above the girdle and 24 and a culet below.
The outer edge of a diamond usually grasped by the mounting.
The 32 facets immediately above and below the girdle.
Any visible internal foreign object, or any crystal or grain of the same material as diamond or any break in a diamond.
A diamond that has been exposed to radiation. Irradiation causes the color of a stone to change. Usually to greenish. May be from a natural or man provided source.
The host rock in all primary diamond deposites.
A diamond crystal embeded in the surface of a host diamond that has been polished or cut.
Small magnifying glass
Unnecessarily thick girdle.
Flat, triangular, rough diamond which is a twinned crystal.
Diamonds under .20 carat.
Old English Cut
Old European Cut
Early round cut characterized by a very small table, heavy crown and great overall depth.
Old Mine Cut
An old cut that is square with rounded corners
Property of some diamonds to continue to emit visible light (be lumimescent) in darkness after exposure to UV rays. To glow in the dark. This is a rare property.
100th of a carat.
As implies, a polished surface of the girdle as opposed to a waxy one. It may also be faceted.
Alternating display of reflections from the polished facets of a diamond as seen by an observer as the stone, light source or the observer is in motion.
A stone that has been cut with a large table and a thin crown.
All facets in a step cut stone are four sided and in steps, or rows both above and below the girdle. All facets are parallel to the girdle and except for those on the corners are long and narrow.
Cut is one of the most important factors in a diamond's brilliance. Since it's all about light optics and the ideal angles to produce the maximum effect the cut is critical to a the beauty of the diamond. The closer a diamond is cut to ideal proportions, the greater brilliance the diamond will exhibit.
Many people confuse cut with the shape of a diamond. The shape you select is a matter of individual taste, and today your choice is only limited by the skill and imagination of the craftsman. It is their effort during every stage of the fashioning process that reflects the maximum amount of light back to the eye.
Most round, brilliant-cut or fancy-shaped diamonds possess 58 carefully angled flat surfaces, called facets, whose placement will affect the fire, brilliance and ultimate beauty of your diamond.
The cut of a diamond is in direct conjunction to the proportion of a diamond.
With proper cutting the light passes through the top, reflects off the sides, and then travels back out through the top, giving the diamond optimum brilliance. If the diamond is cut too shallow, light passes through the bottom of the diamond.
If the diamond is cut too deep, light passes through the side of the diamond, in both cases inhibiting maximum brilliance.
Take a few moments to read
through this page to become familiar with the various popular cuts of diamonds
used in today's finest jewelry.
The most common, and the most "brilliant", diamond cut is the Brilliant Cut, a.k.a. Round Cut, American Ideal Cut, or American Standard Cut.
This design is optically the most efficient, but larger stones (3+ Carats) sometimes look "too big" to some tastes and another cut is preferred.
The Marquise looks something like a football when viewed straight down from the top. It is important to note that with the Marquise and other "fancy" cut stones, you'll want to keep the color quality higher as poor color quality will show much faster than in round cut stones.
The Oval cut diamond
has an elliptical shape when viewed from above. A well cut oval can be
nearly as bright as a well cut round brilliant shape. Trust your eye to
judge the cut of an oval in natural light. It if looks lifeless in the
natural light it is a poorly cut stone. (Do not be fooled by the dozens
of recessed halogen lights in the retail stores.)
Looks like a rectangle from the top, with truncated corners. Color plays a very big role in an emerald cut stone so stay above a 'G' color rating when looking at stones with this cut.
The pear is a popular cut that looks like a tear drop. It is often the preferred cut for pendants and earrings.
Colors tend to play dramatically with the pear cut, as they do in most fancy cut stones, so stay with the higher color quality when selecting a pear cut diamond.
The Trillion Cut is a three sided cut (looking very much like a triangle) but with slightly bowed sides. Many of these types of cuts are trademarked cuts. The fire and beauty of the Trillion cuts make this a spectacular cut of diamond.
There are many variations to the cuts listed above, some are subtle variations and others are extreme. Small rectangular cut diamonds, which look like small rectangular tapered boxes are called baguettes. These have much the same facets of an emerald cut stone but in a much more modern look.