How to Evaluate Loose Diamonds

Many people prefer to buy their diamonds loose, then select the setting that they want later

Loose diamonds are easier to evaluate than set ones because the lack of a setting enables you to access all aspects and facets of the stone. While the factors that go into a diamond's quality are the same regardless of whether or not the stone is set, the evaluation process is a little easier when you do not have to work around a setting. While you should generally have a licensed jeweler, appraiser or gemologist examine diamonds before purchase, you can get a pretty good idea of the quality of the stones by examining them carefully both with the naked eye and under a microscope.

Things You'll Need

• Microscope or jeweler's glass
• Magnifying glass

Instructions

1. 

   Examine the color. Except in the cases of "fancy" colored diamonds, the clearer a diamond is, the better the quality of the stone. You can examine this by viewing it under a bright light. If the stone appears cloudy, milky, or has a yellow or brown cast, then the diamond is not of particularly good quality.

2. Look for dark spots. When viewed from above, a diamond should be bright and sparkling. While most diamonds do have flaws, a good diamond cutter can usually cut so that the facets obscure the majority of the inclusions from an overhead view. If there are visible dark spots in the diamond, either the cutting was sloppy or the inclusions were too large to hide--either way the stone is of lower quality.

3. Check the facets and angles. Diamonds are used to cut many extremely hard substances because of their ability to hold an edge. Facets and the junctions of facets should be very sharp and clearly defined. If they are rounded or worn, you may be dealing with a fake, since nothing can hold a point like a diamond.

4. Verify all incusions. If a diamond appears flawless, you absolutely must verify this with at least one licensed jeweler. Fake diamonds do not have inclusions, so if a deal appears too good to be true, then it probably is. You should be able to identify a diamond by the unique locations and types of inclusions. Large inclusions that are visible to the naked eye decrease the value of a stone dramatically, while smaller inclusions visible only under a microscope or magnifying glass tend to be less of a problem.

5. 

   Rate the "fire." A diamond's "fire" or brilliance is caused by the cut of the diamond and the interior prismatic workings of the stone. If the stone does not flash when it is exposed to and moved under bright light, then it is of lower quality than a stone that sparkles.

Tips & Warnings

• If you are considering buying a diamond, then you likely already know about what size you would like. Generally, the size of the diamond can mean it is more valuable, but if the stone has a lot of problems like the ones explained above, it may be worth less than a smaller, less problematic stone.