American Gem Society
Stanford Shopping Center, Palo Alto   •   650 325–3533 SHOP   •   CART
About Diamonds


The Peninsula's First Choice

If you ever have shopped for a diamond you may have found yourself very confused. There are numbers, letters, and a combination of both, along with acronyms and industry specific terms. All this information can be a bit overwhelming. We believe it’s unfair to have you look at charts and color grades on a computer screen and be expected to become an instant expert. Here at Gleim the Jeweler we pride ourselves on the time we take in sharing our knowledge with you. We give you the opportunity to compare diamonds side by side, letting you see the difference in the color, clarity, cut and carat, helping you to interpret the information. Our role is to help you find a truly special diamond.

Purchasing a Diamond

At Gleims, we believe the entire process of buying a diamond should be a special occasion. That's why from the moment you walk in the door we work hard to make you feel comfortable and to ensure that you select a diamond you will be happy with and proud to own.

Among the most valuable gems in the world, the diamond is the only gem able to maintain its beauty and remain relatively unharmed by a lifetime of wear. A diamond must be properly graded and represented. Here is a brief guide to the Four C’s.

The Four C's


The diamond’s brilliance can be brought out by the work of an expert diamond cutter, whose artistry unlocks the gem's beauty, taking it from being a diamond in the rough to a bright sparkling diamond on your finger.

The beauty of a faceted diamond lies in its ability to refract light and disperse color. The "ideal cut" diamond describes a round brilliant diamond that have been cut to precise proportions using a mathematical formula to produce the maximum fire, brilliance and symmetry. Although the term is widely used, there are very few diamonds that are ideally cut.


With diamonds, even the smallest variation in color can make a big difference. In grading for color we are in actuality grading for the lack of color. The closer a diamond comes to being absolutely colorless the more rare and valuable it is. The presence of color ranges from colorless, to near colorless, to varying tinges of faint yellow and brown.


Most diamonds contain naturally occurring marks called inclusions. The size, nature, location, and number of inclusions determine a diamond's clarity grade, ultimately affecting its overall value. All diamonds are graded by 10x magnification. Since these naturally occurring “birthmarks” are inherent they shouldn’t be considered to be defects.

Carat Weight

The universal unit used to measure a diamond is the carat. A carat can be divided into 100 equal parts called points. For example a .50ct diamond is half of a carat, and a .75ct is three quarters of a carat. The larger the diamond the more rare, thus increasing the value exponentially. A diamond that is twice the size of another of similar quality will be worth four to five times as much.

It's important to remember that weight is just one factor in determining the perfect diamond. The value of two diamonds of the same weight can vary greatly depending on the color, clarity, and cut.

For over 80 years Gleim the Jeweler has been helping our community select the perfect diamonds.

Vintage Diamond Brooch

Diamond Color Chart

Diamond Color Chart


Diamond Clarity Chart

Diamond Clarity Chart