| Gems Guide |
How to buy a gemstone
Here In Gemstone Buyin g Guide we are trying to tell you about gemstone quality. After finishing our gemstone buying advice, you will know more than the average jeweler. But you have to go through ALL our gemstone buying advice: gemstones are much more complicated than diamonds (which is why most jewelers don?t know much about them). So concentrate! Gemstones have no grading system, each variety has individual value factors, and within each gem variety, quality dramatically affects price: a ruby can be worth $10 or $1,000,000. Everybody agrees what the best stone is, that?s easy. But the best buy? That?s tricky. Hold on, we?ll take you there! First, the basics. Like diamonds, gemstone quality and value are evaluated according to the "four Cs": color, clarity, cut, and carat weight. For ruby, sapphire, and to a lesser extent emerald, country or origin also affects value. Unfortunately, colored gemstones are also commonly treated, so that also affects value for ruby, sapphire and emerald in particular. Let?s start with the most important gemstone value factors, color, clarity, and carat weight.
Judging Color
Color is the important factor. But its not true that the darker the color, the better the stone. Atleast not correct every time: color can be too dark, like some sapphires that look more black than blue. Think grass green, not forest green. Fire engine red, not burgundy. The more bright and vivid the color, the better.
In precise grading terms: clear, medium-tone, intense and saturated primary colors are the most preferred. Pure blue, not greenish blue. Pure red, not purplish red. Muted colors and colors between hues, which you might find very attractive, are usually less expensive. Look at the color in different kinds of light.
Judging Clarity
The next most important factor affecting value is clarity: clear transparent gemstones with no visible flaws are the most valued . There is no standardized grading system for clarity: it varies by gem variety. With colored gemstones, if the inclusion doesn?t show in the face up position, it generally doesn?t matter at all. (unlike diamonds which are graded upside-down at 10x magnification). Some varieties, notably emerald and red tourmaline, are very rare without inclusions of some kind so the price structure takes this into account. Pastel colored gemstones show inclusions more, so they generally detract more from the value for pale stones.
In rare cases, inclusions can increase value. Special effects like the star in star sapphire and the eye in cat?s-eye chrysoberyl are caused by inclusions. Inclusions can also be a birthmark, proving that a gemstone is from a particular place. So "horse-tail" inclusions in demantoid garnet make it more valuable because they prove it came from Russia. But more about origin later.
Carat Weight and Prices
Gemstones are sold by weight, not by size. Prices are calculated per carat, which is one-fifth of a gram. Some gems are denser than others so the same weight stone may be a different size! For example a one-carat emerald is a bigger than a one-carat ruby. Just like diamonds, the carat weight also affects the price: large gemstones are more rare, so the price per carat is higher. But practically, this doesn?t make much of a difference with common gems like amethyst, citrine and blue topaz. It really kicks in for ruby, emerald, sapphire, and demantoid garnet,tourmaline, spinel, and pink topaz.
Another important quality factor, which makes a big difference in a gem?s beauty, but may not add much to the price is cut?
| Judging Cut A good cut is something that may not cost more but can add or subtract a lot of beauty. A well-cut faceted gemstone reflects light back evenly across its surface area when held face up. If the stone is too deep and narrow, areas will be dark. If it is too shallow and wide, parts of the stone will be washed out and lifeless. The best way to judge cut is to look at similar gemstones next to each other. Look at these three stones. See the dark areas in the stone on the left and right? These are caused by light leaking out the back of the stones because the angles aren?t right. Look for a stone like the one in the middle which has even brilliance. Colored gemstones come in lots of different cut variations, many more than diamonds. Choose whichever cut style appeals to you: just make sure that the angles are right and light is coming back to the eye in a pleasing way. In addition to choosing different gem cuts, try different varieties. Even in red, blue, and green, there are lots of gem alternatives. |
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