Diamond Guide
Most diamonds produced for the general market are cut in a way that will maximize carat weight, not beauty.   The shape of the rough diamond determines the cut.   Consequently, many diamonds are either too deep or too shallow.   A diamond that is cut too deeply or too shallow will allow light to pass through the bottom of the stone.
The Ideal Cut:
The Ideal Cut diamond is a diamond that has been cut to exact mathematically proven proportions with the goal of producing the most beautiful diamond possible.   Maximizing light return, rather than carat weight, is the highest priority for a master cutter striving for the Ideal Cut.   Consequently, a cutter must sacrifice weight in order to achieve the Ideal Cut.   Hearts and Arrows Super Ideal Cut diamonds are the premier Ideal Cut diamonds.
The Star 129 Cut:
The STAR 129 is a new round cut that has been developed using modern technology.   Unlike the traditional 58 facet round brilliant diamond, a STAR 129 has 129 facets.   Like the Ideal Cut, the STAR 129 diamond is cut to maximize brilliance.   We have seen several new facet designs over the years, but none have been able to outshine the Hearts and Arrows Ideal Cut.    The STAR 129 far outshines the others, including the Hearts and Arrows Ideal Cut, for overall brilliance and beauty.
Common Shapes:
The most popular shape, Round Brilliant Cut, has the highest potential for brilliance.   Although the Marquise, Oval, or Pear shaped diamond can be quite good if well cut, they usually have a bow-tie shaped dark area in the center.
Emerald Cut diamonds, when cut well, especially in larger sizes (over 2 ct.) can be quite impressive.   At their best, they display large rolling flashes of color across the face of the stone, which you do not find in cutting styles with small facets.   Baguette Cuts are like the Emerald Cut diamonds without the corners.
Most diamonds appear colorless, but are actually slightly yellow.   Colorless diamonds are the rarest.   The more color in the stone, the lower its value will be.
Carat Weight and Value:
The rarer the gem, the more valuable it is.   Larger diamonds are more valuable than smaller ones, because there are fewer of them.   However, the price of a diamond does not go up at the same rate as the weight.   For instance, if a 1/2 carat diamond costs $2000, a 1 carat diamond of the same color, clarity, and cut could cost more than $6,000 (more than twice as much).
How big is a Carat?:
A carat is equivalent to 1/142 of an ounce.   That means that it would take 142 (one hundred forty-two) 1 ct. diamonds to weigh an ounce.   The carat was derived by ancient Mediterranean people who used the weight of a carob tree seed as a unit of measurement.  One carat is divided into 100 points.   So a quarter carat diamond would be a 25 point diamond. Likewise, a .19 ct. diamond would be a 19 point diamond.
Cutting for Carats:
As a matter of practice, most diamonds are not cut to the ideal proportions.   Instead they are cut for maximum weight retention, giving consumers the illusion they are getting more diamond for their money.  This is how it works.   A rough diamond crystal that is 6mm across will produce a 3/4 ct. diamond if it is cut for maximum beauty.   Because of the shape of a typical diamond crystal, the cutter can leave some extra on both the pavilion (bottom) and the crown (top), and end up with a 1 ct. diamond.   Now the 1 ct. weight diamond can be sold, even though it is of a less quality, for the same price as a 3/4 ct. diamond from GB Jewelers.   You can bet that retailer store will not display the "bargain priced" 1 ct. diamond next to a properly cut diamond.   Side by side, the comparison would be obvious.   It will be smaller, having a 6mm diameter rather than the 6.5mm on a properly cut stone.  Also, because of the improper proportions used to produce the additional weight, the 1 ct. diamond will be a lot less brilliant.
Certificates are issued to certify the various qualities of a diamond (or other gemstone) by an independant organization.   These certification agencies are not involved in the buying or selling of diamonds.   These many agencies command different levels of respect in the industry.  
The Major Players:
GIA (Gemological Institute of America) is a leader in diamond grading and gemological education.
  • Most respected for their color and clarity grades.
  • Offers courses to become a graduate gemologist.
  • Also will evaluate colored gemstones.
AGS (American Gem Society) is a non-profit organization dedicated to maintaining high standards in the jewelry trade in America.
  • Most respected for their cut grades.
  • AGS 000 grade (best cutting grade) most highly respected ideal cut grade.
HRD (Hoge Raad Diamant or Diamond High Council) is a Belgian governmental organization dedicated to promoting diamonds in Antwerp.
  • Most respected for their color and clarity grades.
  • They are not widely known in America.
EGL (European Gemological Lab) is a for-profit grading organization.
  • Has several independently run labs in various regions of the world.
  • A reputation for overgrading in the past (sometimes referred to as "Easy Grading Lab").
  • Has been trying to redeem themselves recently.
  • Newer grades are better than older ones.
IGI (International Gemological Institute) is a for-profit independent grading organization.
  • Notorious for their generous grading.
  • Offers appraisals with their certificates.
  • Their appraisals are often much higher than market value and are often used to offer big discounts off of those values.
AGTA (American Gem Trade Association) is an association of natural colored gemstone professionals dedicated to maintaining the highest ethical standards among its members and within the industry.
  • Provide certificates for heat treatment and country of origin of colored gemstones.
  • Known for having very high standards in their gemstone evaluations.
GRS (Gem Research Swisslab) is a gemological research company focused on the identification of gemstones from all over the world.
  • Provide certificates for heat treatment and country of origin.
  • Commonly used to certify rubies and sapphires.
Note:   There are several smaller organizations, some of which only have 1 customer.   Big corporations often use these organizations in order to get the grades they would prefer.
Why would I want a Certificate?:
Certificates allow buyers to be confident that they get what they pay for.   For non-experts it's a way to have an expert, not involved in the sale, grade the product.
How much does a Certificate cost?:
Certificate costs depend on the certification agency.   The cost of a certificate is usually determined by the weight of the diamond (per carat basis).
GB Jewelers, Inc.
Under the Clock Tower
675 SE Marlin Avenue, Suite 1  /  PO Box 999
Warrenton, OR 97146

Latitude:  46.159033 / Longitude: -123.9055280
Store Hours: 10:00 a.m. - 6:00 p.m.
Monday - Saturday
We are closed on Christmas Day and on New Years Day every year.
Copyright 1974