Colored gemstones are among the most popular center and accent stones for jewelry items. Here, we present the basics of colored gemstones.
Gemstone 4 C’s
While there are no official 4 C’s for grading colored gemstones like there are with diamonds, many of the same principals apply. Following are the 4 C’s as they apply to colored gemstones:
Clarity in most gemstones does not influence its value or beauty unless it breaks the surface or affects the integrity of the gemstone. In lighter colored stones, clarity may be more important than in darker stones that can mask imperfections. However, flawlessness in colored games is even rarer than in diamonds.
The four flaws that occur in gemstones are fault, fissure, fracture and gas bubbles. It is the type and location of a flaw that is more important than the fact that there is a flaw, since some flaws can affect the stone’s durability. Some stones are typically eye-clean such as topaz, while others are expected to have inclusions, such as emerald.
Color has the greatest impact on value. The color should be pure, vibrant, even and fully saturated without being too dark or too light.
Cut affects the amount of brilliance the gemstone returns to the eye, the depth of color seen and the size of the stone. Well-cut gemstones will enhance the color of a stone, while poorly cut gemstones can end up looking flat and lifeless.
Carat weight determines values in two ways. First, the carat weight x price per carat = total price for the stone. Second, the rarity of the size of stone compared to the normal size found will affect the price.
Many gemstones have historically and traditionally been enhanced before bringing them to the customer. Most enhancements have been around for a very long time, some for hundreds of years or longer. The result is an improvement on nature’s beauty. It makes gems available and affordable. Most of these enhancements are stable and no special care is required.
Gems that are not usually treated include alexandrite, black star sapphire, cat’s eye chrysoberyl, garnets, hematite, iolite, moonstone, peridot, spinel and chalcedonies such as bloodstone, fire agate, onyx and sardonyx.
Specific Colored Gemstones
Many colored gemstones are also recognized as “birthstones,” with each one popularly and historically associated with one of the twelve calendar months. Learn more about each:
- January: Garnet
- February: Amethyst
- March: Aquamarine
- April: Diamond
- May: Emerald
- June: Pearl
- July: Ruby
- August: Peridot
- September: Sapphire
- October: Opal
- November: Topaz
- December: Turquoise
Precious vs. Semi-Precious Gemstones
The difference between precious and semi-precious gemstones is rarity. Diamonds, rubies, sapphires and emeralds are very rare and are therefore considered to be precious stones; all other gemstones are considered semi-precious.
Natural vs. Lab-created Gemstones
Natural gemstones are found in nature. They are created in and mined from the earth. Natural gemstones are sometimes enhanced, which means they were treated in some way (such as heat) to improve their color and/or clarity.
Lab-created gemstones are made in laboratories and are chemically, physically and optically identical to gems found in nature. Lab-created gemstones simply do not have the rarity or value of natural gemstones.
Color, Cut and Clarity
- Color- sometimes referred to as the gem’s hue. Generally, gemstones with clear, medium-tone, intense and saturated primary colors are most preferred.
- Clarity- appearance of inclusions in the gem. Some gems, such as emeralds, are more likely to have inclusions, while gems like aquamarine and topaz generally have very few or no inclusions.
- Carat- weight of the gemstone. It is important to recognize that some gems are denser than others, so similarly sized stones of different varieties may differ greatly in cost. For example, a one carat ruby (very dense) is going to be smaller than a one carat emerald (less dense).