San Francisco Diamond - ValuExchange

Diamonds

Diamonds are the most valuable of rare gems for a number of reasons. Their brilliance, durability and scarcity are unsurpassed. They are the worldís hardest natural material. They possess a broad range of color, high refraction, high dispersion (or "fire") and a low reactivity to chemicals. Perhaps most importantly, no diamond is like any other, which helps to make finding an ideal one a thrilling process.

Diamonds are appraised according to criteria that are relatively easy for most consumers to understand. They are:

Shape & Cut

A diamondís brilliance comes from the quality of its cut. To be considered well cut, a diamond must have the right proportions, symmetry and polish. A well-cut stone is carefully crafted and polished until it sparkles. Its brilliance and fire are apparent because the stone delivers the maximum amount of light passing through it to the eye.

A poorly cut stone looks lifeless because the light that enters it from above escapes through the sides and bottom , diminishing the sparkle or fire, regardless of the stoneís color or clarity.

Inferior Cut Light Example - Too Shallow Cut Too Shallow

When a diamond is cut too shallow, light escapes through the bottom, reducing the brilliance of the stone, making the general appearance watery glassy and dark.

Inferior Cut Light Example - Too Deep Cut Too Deep

When a diamond is cut too deep, light escapes through the bottom, reducing the brilliance of the stone, making the center appear dark.

Ideal Cut Light Example Ideal Cut

Light entering the diamond reflects internally from facet to facet and is reflected back out only through the top. Therefore, an ideal cut yields maximum brilliance.

An Ideal cut employs the strict mathematical proportions referenced below. Ideal cuts apply only to round diamonds, because symmetry is required for maximum light reflection.

Ideal Cut - Mathematical Proportions

But an ideal cut is not possible in every case. The rough diamondís natural inclusions, or imperfections, sometimes make it impossible to apply perfect proportions during the cutting process.

A Very Good cut reflects back up to 90 percent of the light entering the stone. An ideal cut is considered extremely well-proportioned.

A Good cut applies to a stone that reflects back lots of light. Stones with good cuts are often used in high-quality jewelry.

A Fair cut is used to make the most of the weight of the original stone, which tends to reduce its brilliance and fire. A fair cut reflects back as little as 50 percent of the light that has passed through the diamond.

A Poor cut diamond looks lifeless to the eye. We do not offer poorly cut diamonds for sale to our customers, and we donít recommend them for fine jewelry. When you consider a diamond's cut, you should also check the diamond's specifications against the following table to determine whether the polish, symmetry, girdle and culet of the diamond fall within acceptable standards.

Color

A diamondís color is another indicator of its value. The closer a stone is to colorless in other words, the less color that is apparent the more value it has. The diamondís value drops at the first sign of yellow or brown hues.

A gemologist rates a diamondís color using a GIA letter scale. The grades D to F indicate that the stone appears colorless when viewed by the naked eye. People prize these diamonds because they allow a maximum amount of light to pass into the stone. Diamonds in the G to J range appear nearly colorless, but a trained professional can see a faint yellow cast. In diamonds graded K to M, the untrained eye can detect some color, but these diamonds are still desirable as affordable jewelry. Ratings of L and below indicate a noticeable yellow tint, which some people prefer on aesthetic grounds.

Clarity

What determines a diamondís clarity? The number of natural imperfections, or inclusions, and other imperfections. These imperfections are the primary things that make each gemstone unique. The majority of inclusions are so small that they can only be seen under a microscope.

FL - IF VVS1 - VVS2 VS1 - VS2 SI1 - SI2 I1 - I3

Gemologists refer to grades of clarity when they describe how many inclusions a diamond has. These grades are based on a scale that ranges from flawless (FL) through included (I3) as illustrated below. (The chart below is typical of the diamond maps shown on diamond certificates).

Your certificate helps you evaluate the clarity of your diamond, which, in addition to color and cut, is an important measure of its value.

Carats

Diamonds are measured by weight. The unit of measurement is called a carat, which equals 0.2 grams, or 200 milligrams. Large diamonds are more scarce than smaller ones, so theyíre generally more valuable and have a greater value per carat. For example, a two-carat diamond is always more expensive than two one-carat diamonds of the same quality.

Certification

A diamond certificate describes, outlines and rates the following characteristics of the diamond:

Rest assured that when you purchase a diamond from Diamond Importers, youíre buying a stone that qualified gemologists have analyzed and graded. The following labs are respected in the diamond trade for providing the most accurate, unbiased grading reports:

American Gem Society (AGS)
Gemological Institute of America (GIA)

Every certified diamond comes with an original certificate describing the characteristics of the diamond.

Here are some sample certificates.

Example Diamond Certificates

Dossier

Dossier certificates give you all the information that full certificates offer. A diamond with a Dossier certificate is automatically inscribed with a certificate number. As a result, no mapping of inclusions is necessary on the Dossier certificate, which is provided for any diamond under one carat. A G.I.A. Dossier certificate offers you the same sense of security that you get from a full G.I.A. certificate.

The certificateís number is laser inscribed by the lab on the girdle of your diamond. The inscription does not effect the cut, color, clarity, or brilliance of your diamond. The inscription is also clearly stated on your certificate

Now you can buy a diamond with peace of mind.

Dossier

Dossier certificates give you all the information that full certificates offer. A diamond with a Dossier certificate is automatically inscribed with a certificate number. As a result, no mapping of inclusions is necessary on the Dossier certificate, which is provided for any diamond under one carat. A G.I.A. Dossier certificate offers you the same sense of security that you get from a full G.I.A. certificate.

The certificateís number is laser inscribed by the lab on the girdle of your diamond. The inscription does not effect the cut, color, clarity, or brilliance of your diamond. The inscription is also clearly stated on your certificate

Now you can buy a diamond with peace of mind.

Diamond Care

Usually, all you must do to restore a diamond's sparkle is rub it gently with a soft brush in a solution of ammonia and warm water. We also recommend that you have the stone cleaned ultra-sonically every once in a while. And, to reveal loose prongs and wear, bring it to your local jeweler for spot checks periodically.

Glossary

Blemish:

A flaw or abrasion on the surface of a diamond.

Brilliance:

Cutting a diamond to the correct proportions maximizes its brilliance, defined as white light reflected up through the stoneís surface.

Brilliant Cut:

A brilliant cut utilizes 58 facets. It can be heart shaped, pear, oval, radiant or round.

Carat:

The unit of weight by which diamonds are measured. One carat equals one-fifth of a gram.

Clarity:

A grade that indicates how many inclusions a diamond has. The scale ranges from Flawless (FL), which means that the diamond has no flaws inside or on its surface, to Severely Included (I3), meaning a diamond has numerous flaws that can be seen without magnification.

Cloud:

A group of small inclusions inside a diamond.

Color:

A grade that indicates the color of the stone. The scale ranges from D, completely colorless, to Z, which refers to an easily noticed yellow tone. The higher the letter in the scale, the more distinct the stoneís yellow or brown cast.

Culet:

Culet can be seen as a miniscule focal point where the pavilionís facets converge.

Cut:

Refers to both the shape of a stone (heart-shaped, oval, round, etc.) and the make (the precise proportions that result from the diamondís cut). The stoneís make determines how much sparkle it reflects more than any other factor.

Cut, Ideal:

Refers to perfectly proportioned, round diamonds that receive high grades on symmetry and polish. The finest craftsmanship enhances the beauty of these stones.

Cut, Very

A diamond with this cut adheres to strict requirements for uniform proportions that make the most of the stoneís brilliance and fire.

Cut, Good:

This diamondís cut displays proportions that are acceptable but not perfect. It has very good fire and brilliance.

Cut, Fair:

This cut makes the most of the diamondís weight, which often results in less fire and brilliance. A diamond with this cut is less expensive than a diamond with a Good or Very Good cut, but it will not sparkle nearly as much.

Cut, Poor:

Poorly cut diamonds appear lifeless. We do not recommend stones with this cut.

Depth:

This refers to a diamondís height, as measured from the culet to the table.

Depth Percentage (%):

The depth percentage, divided by the width of the diamond, mitigates the brilliance and fire in the stone. A diamond lacking sparkle probably has a depth percentage that is too shallow or too deep.

Eye-clean:

Refers to a stone with no flaws visible to the naked eye.

Facet:

The diamondís flat, polished surfaces. A round brilliant diamond possesses 58 facets.

Fire:

The sparkle, or colored light, that a diamond reflects from the light passing through it.

Fluorescence:

A glow, often bluish in hue, that emanates from some diamonds when theyíre bathed in ultraviolet light. Avoid high degrees of fluorescence; faint to medium fluorescence, however, usually does not change the diamondís appearance.

Girdle:

A diamondís girdle is a thin band that traces the stoneís diameter.

Inclusion:

Inclusions, or tiny flaws, are created during the diamondís formation underground. They are fractures, mineral traces, and other imperfections that contribute to the stoneís uniqueness.

Make:

The stoneís proportions, as determined by its cut. The better the make, the more fire and brilliance in the diamond. A worse make results in the stoneís inability to reflect light well, which means it will sparkle less.

Pavilion:

The diamondís bottom area, from just under the girdle to the culet.

Point:

A measure of weight equivalent to one one-100th of a carat. (50 points = 0.50 carat)

Polish:

A grade assigned to the stoneís outer finish. The grading scale ranges from excellent to poor.

Symmetry:

A grade assigned to the cutís overall uniformity. The grading scale ranges from excellent to poor.

Table:

The stoneís largest facet, situated on its top.

Table Percentage (%):

The tableís width divided by the diamondís diameter. A proper table percentage is necessary for a diamond to sparkle. A too-low or too-high table percentage will make the stone duller.

Quality

At ValuExchange / Diamond Importers, we select our diamonds according to strict quality standards for color, clarity and cut. Each of the thousands of diamonds in our selection has been analyzed, graded, and inscribed by the Gemological Institute of America (GIA), the most respected authorities on diamonds.

When you purchase a loose diamond from ValuExchange / Diamond Importers, you will receive a copy of the Diamond Certificate issued by the GIA. It guarantees the cut, clarity, color and carat weight of your diamond.