Jewelry Gemstones Knowledge - Precious Stones

An Overview of Colored Stones

Alexandrite

A most unusual and unique stone for its color change when it is exposed to light in different forms. Alexandrite looks blue-green when it is seen under the equivalent of natural daylight. When viewed under indoor light, the appearance is reddish-purple. Mining of natural alexandrite has stopped, therefore the stones that have good color are very valuable. There are several versions of alexandrite imitations in the market to be aware of.

Amethyst

A type of quartz ranging in color from light lavender to a deep, intense purple. Because amethyst is so widely available in the jewelry market, it is not too valuable or expensive. Uniquely, amethyst is always a variety of purple. It is very commonly used in jewelry.

Aquamarine

A gem ranging in color from deep blue or blue-green to light blue. The most valuable aquamarines are the ones that exhibit a pure blue color. Aquamarines are often faceted, however there are some which are not. Some of the highest quality aquamarines originated in Russia. This stone is very popular and widely used in jewelry.

Black Onyx

It is a form of quartz. Onyx is not always black, but is most popular in jewelry in black. It also exists in white, tan, and brown. It is usually cut in the shape of a cabochon and sometimes found in the form of beads. Also commonly used for intaglios and cameos.

Citrine

Citrine is a variety of quartz that can range from brown to red-orange to yellow. This stone, usually found in gemstone form, is not as bountiful as the more common gemstones. Most citrines found in today’s marketplace have actually been heat treated.

Emerald

High quality emeralds are among the most valued of all gemstones. A precious gemstone variety that is deep green colored. Flaws or inclusions are very common in emeralds, which makes their value less affected than that of diamonds or other gemstones. Columbian emeralds are among the most highly regarded emeralds. A high quality emerald has a deep green color, with the most valuable having a slight blue tinge to its green color. If an emerald appears high quality and has no inclusions, it is most likely synthetic. Most emeralds that are used in jewelry are of lower quality and have been artificially enhanced to improve their appearance.

Garnet

Garnets are most commonly found in Turkey, Russia, and the U.S. Usually found in a dark, crimson toned red, this semi precious stone can also be found in a range including deep red to deep purple to brown, orange, green, or blue. Blue is the most rare of these colors. They can range in quality from cut and polished gemstone quality that allows light to pass through to opaque stones mainly used as abrasives.

Jade

Made up of two mineral varieties, jadeite and nephrite, jade has been treasured by the Chinese and Indian population for thousands of years. Jade can be green, lavender, red, black, and yellow. Simulated jade is quite common and it is usually made of glass or plastic.

Lapis Lazuli

Made up of many different minerals, lapis lazuli is a vibrant toned blue and green natural stone. The colors that lapis lazuli exhibits range from royal blue to violet to greenish blue to forest green. Has a medium hardness of 5-6 on the Mohs hardness scale, and also has a softened luster.

Opal

Opal is a semi precious stone that has a speckled and multi-colored iridescent look. Viewed in different lighting or angles, opals give off a somewhat rainbow effect of a plethora of colors. Opal also has a medium hardness or 5.5 to 6.5 on the Mohs hardness scale.

Peridot

A semiprecious green colored gemstone that ranges in color from a vibrant green to a yellowish green or even an olive green or a deep green.

Ruby

Ruby is a red precious gemstone. Color in rubies can range from a deep blood red to magenta. Very fine rubies can be worth even more than diamonds. Ruby is in the corundum species. Star rubies also exhibit a star-like phenomenon, known as asterism.

Sapphire

Sapphires are most commonly found in blue, they also exist in a wide range of colors like white, orange, pink and green. Sapphire is also a precious gemstone and in the corundum species. Star sapphires are also quite common, they exhibit a star-like phenomenon, which is referred to as asterism.

Topaz

Topaz comes in a multitude of colors, including yellow, orange, pink-red, red-brown, etc. It is a precious gemstone that is an 8 on the Mohs hardness scale.

Tourmaline

Tourmaline has an extremely wide color range . It ranks a 7.5 on the Mohs hardness scale. Two or more colors can be exhibited in the same crystal in a tourmaline.