Let's begin with a few definitions relative to the anatomy of a faceted stone. A cut stone can be divided into three areas - the top portion, called the crown; the bottom portion, called the pavilion; and the portion of the stone that separates the top and bottom, called the girdle. The girdle is generally the widest part of the stone. The largest facet on the crown, is the table, which is located at the very top of the stone. The cutlet is the pointed portion on the very bottom of the pavilion. There are numerous names for the remaining, smaller facets, but we won't dwell upon them for this discussion.
Matlins and Bonanno suggest using six key steps while examining a stone for possible purchase:
- If possible, examine the stone unmounted. The stone can be examined more thoroughly and defects spotted more easily when the stone is not set.
- Make sure the gemstone is clean. It is hard to look for defects if the stone has a thin layer of dust or body oil on it. If the jeweler cannot clean it, fog the stone by breathing on it in a fashion similar to cleaning eyeglasses and wiping it with a clean cloth.
- Hold the stone so that your fingers only touch the girdle. Jeweler's tweezers are really the preferred method for holding the stone, so, ask your jeweler if he or she has them available for your use. Be careful, however, that the jeweler will not hold you responsible for any stones that pop out of the tweezers, which commonly happens.
- View the gem under proper lighting. Incandescent and fluorescent lighting can adversely affect the general appearance of the gemstone. If possible, view the stone under natural daylight conditions. Also, the light source should come from above and behind you, so that the stone will select the light back to your eye. Don't hold the stone between you and the light source.
- Rotate the stone and view it from different angles.
- If you use a jeweler's loupe - basically a glorified magnifying glass - focus it on the surface and then into the interior. If you don't have a loupe, ask your jeweler for one.
If you are using a loupe to identify potential flaws, then you should be using a 10 power loupe - one that will magnify the stone 10 times its normal size. Keep in mind that higher-power loupes are available, but a gemstone is only considered to have flaws if they are visible under a 10-power loupe.
So, what can a loupe tell you? For one thing, it can tell you what kind of workmanship went into cutting the stone. When you look at the stone, imagine slicing it into half from different orientations. Do the two halves mirror each other? Does the stone look balanced? If you are familiar with the different types of cuts, does the stone have the proper number of facets for the cut? A loupe can also help you spot chips and scratches. Take time to examine both the table (the large, flat top facet) and the edges of the facet cuts. Often, people will focus only on the flatter portions of the stone and not enough on the edges where the facets meet. Also, check the facet edges to see if they have sharp, definitive boundaries. If the stone is set as a piece of jewelry, check around the prongs or bezels for scratches from setting tools. Check to see if the stone has been glued on the prongs or bezel. A properly set stone should not be glued.
A loupe can help you check for bubbles, inclusions, cracks and other flaws. Most of these types of blemishes will be in the interior of the stone. Bubbles and inclusions may show up as cloudy areas in the stone. Cracks tend to show up as linear features. Finally, a loupe can help you identify certain enhancements made to the stone, such as whether two or more stones have been joined together - something called a doublet and triplet. Doublets and triplets can usually be identified by looking at the side of the stone for a linear feature, where the two or three stones have been joined together.
While examining the stone, ask questions of the jeweler. Most jewelers are reputable, and will try to answer your questions to the best of their abilities. You can ask about carat weight of the stone, the types of cut and how many facets a particular cut should have. You might also ask if the stone is natural or simulated (i.e., man-made), whether it is a genuine stone or imitation, and whether it has been enhanced (a natural stone that has been treated).
Be wary of marketing labels, as they can be misleading. For example, there are misnomers like smoky topaz that is not topaz at all - it is smokey quartz. So, if you are unsure, ask the jeweler if it's the real deal. If they want to protect their reputation - and most do - they'll be honest with you.
I hope I've armed you with information to assist you with making a more informed decision during the holiday season. For now, we wish you all a happy holiday season.