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When you are purchasing a new piece of jewelry or a gem you need to know what makes a good quality gem, versus a poor quality one: shape, cut, carat weight, color, and clarity.
The shape of a gemstone refers to its physical outline when looking at it from the top. Gems can be cut into any shape possible - like a moon, star, animals or abstract forms. These cuts are unusual and rare. There are six shapes that are the most common: round, marquise, pear, heart, oval and cushion. The marquise is oblong and pointed evenly on the top and the bottom. The pear, looks like an upside down pear, rounded on one end and pointed on the other. A heart is cut like a heart, and an oval is cut into an oval. A cushion cut is a rectangle or square with rounded corners. When cutting a gem it is important for the cutter to emphasize the stone’s color and brilliance, and to minimize it’s flaws. Sometimes there will be a lot of weight loss in the stone to achieve this the perfect cut. Jewelry manufacturers want standard sizes and shapes for mass production, so many cuts have become commonplace.
As for the type of cut, a gem can be cut in different styles to emphasize the stone's beauty. Sometimes the cut is referred to as the facets of the gem. Facets are varying degrees of polished surfaces in different sizes. For example, a gem can have clipped off corners and have four parallel rows on the sides. The amount of clipped corners and the lengths of them will make a difference on how the gem catches and glistens in the light. The flat part on the top of some cut stones is called the table. The amount of facets cut in the gem can make a stone look fancy, elegant, subdued, sparkly, romantic and more.
The weight of a gem is referred to as “carat”. This term began centuries ago when gemstones were put on a scale with carob beans on one side. The weight of the carob bean was referred to as carat weight, each bean weighing one carat. In the early 1900’s carat weight was adjusted to the metric system. One carat is equivalent to 1/5th of a gram. Gems smaller than one carat are described in points; one point equals .01 of a carat. Twenty five points would be .25 or 1/4 carat. Fifty points is .50 or a half a carat.
Usually the higher the carat weight of the gem, the more it will be worth. If you have a ring and the combined weight of a bunch of smaller stones is one carat, this will not be worth as much as a single stone of one carat. So, it is important to pay attention to the carat weight of one stone and the total weight of the entire ring.
The color of a stone will also be a determining factor in it's value. Color is hard to describe in written terms; many people have different interpretations about what a color looks like. The color of stones has been standardized in different ways by different organizations. One of the organizations is the Gemological Institute of America or the AGI. This institute uses three aspects when deciding a gem's color. Hue, or the basic colors of blue, green, yellow, orange, violet, purple and red. Tone, which is the lightness or darkness of the gem’s color. Color purity is used to describe a stone that may have it’s hue hidden by brown or gray; or whether the gem is pure or cloudy. A stone that is vivid and bright in color, is more valuable than a stone that is cloudy, muddy or dull. A stone that is light will not be as valuable as a medium dark stone. But, a gem that is too dark is not as valuable as a medium dark one either. A light colored gem can be just as beautiful as a medium colored gem, but there is more demand for the darker gem and thus the value is higher based on this demand.
To determine the color and hue of a stone, dealers use a color grading chart. You can determine the color of a stone while you are shopping with some easy steps. First, bring a soft cloth with you and wipe the fingerprints and dirt from the gem. Examine the color against several different backgrounds such as, white to see if the center of the stone is pale and washed out. Examine the gem in the bright light. If you are looking at earrings be sure to compare both of them together to make sure they are of the same color and hue. Look at the gem next to your skin to make sure it will look good on you. If an expensive gem doesn’t look good next to your skin, then there is no reason to buy it.
Incidentally, diamonds are more valuable if they have no color. If a diamond has a yellow or gray hue it is not considered colorless and therefore not as valuable.
Clarity is another factor that a gem will be judged upon. Clarity in a gem is determined by how clean and free of flaws it is to the human eye. A stone can have spots, cracks or crystal inclusions that may affect it’s transparency. Some stones such as emeralds and rubies commonly have spots or flaws. But these should not necessarily be considered flaws or negative aspects in the gem, it is simply a normal characteristic of the stone. Stones that usually have high clarity are aquamarine, ctirine and topaz. If one of these stones had a flaw or spot it would negatively effect it’s value.
Each month of the year is represented by a different gem.
January is a garnet; usually a deep red gem that resembles a pomegranate. Garnets can be found in nature in every color except blue.
February is an amethyst; it is a member of the quartz family and the color is varying degrees of purple.
March is aquamarine; it comes in varying shades of light blue to sea blue.
April is the diamond; the color is brilliantly clear.
May is the emerald; the color is a deep green.
June is the pearl; made in the oysters of the sea, they are round and white to deep black.
July is the ruby; a red gem that is more solid looking than a garnet.
August is the peridot; a very light green.
September is the sapphire; a deep blue.
October is the opal; a rainbow of iridescent color on a light background.
November is citrine; a bright yellow/ orange.
December is topaz; most popularly in light blue.
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