Buying Gemstones

The 4 C's - Clarity, Color, Carat and Cut

Although traditionally the 4 C's are relevant to Diamonds, they can be used as a guide when buying gemstones.

Clarity: Transparent gemstones, which have no visible flaws are the most valued. Generally if inclusions do not show up face up on a gemstone, it doesn't matter. Is some rare cases inclusions can increase value, such as the eye in a Cat's Eye gemstone.Amber Ring

Color: The color of a gemstone is a key factor when buying. The more vivid, saturated and bright the color is, the better.

Carat: The price of a gemstone is calculated by weight, per carat, which is one-fifth of a gram. Larger gemstones are rare, therefore the price per carat is higher. This affects more precious gemstones such as Diamonds, Rubies and Sapphires.

Cut: A well cut gemstone, will increase its beauty. A faceted gemstone should reflect light evenly across its surface. The easiest way to judge whether a gemstone is well cut is to compare gemstones next to each other. Gemstones cut too wide and shallow, appear lifeless and if cut too narrow and deep, appear too dark.

General Questions

Generally, the price of any gemstone is determined by: size, cut, quality and type. Some general questions you should ask about quality are below:

  • Has the gemstone been treated? (See below for details of treatments)
  • Is the gemstone natural or synthetic?
  • Are there any noticeable scratches, chips or inclusions?
  • Is the color even throughout the stone?
  • How good is the gemstone color?
  • If buying the gemstones for earrings or cufflinks, are the stones well matched?

Gemstone Treatments

There are a number of ways a gemstone can be treated.

  • Irradiation is used to bring out the color of a gemstone. Aquamarine, Blue Topaz, Emerald and Diamond are common gemstones to irradiate.
  • Heat - Amethyst, Aquamarine, and Topaz are often heated to enhance color.
  • Dye - Lapis Lazuli, Amethyst and Citrine are often dyed. Note that dye may be visible in cracks on clear stones.
  • Coating - Gemstones are dipped in petroleum or oil to bring out the color and seal it.

Aquamarine Gem
Aquamarine		 Topaz Crystal
Topaz		 Amethyst Crystal
Amethyst		 Emerald
Emerald

If a stone looks too good to be true, it may be fake, irrdiated or dyed.

Remember to consult the glossary if unsure of gemstone terms.