Beautiful gemstones have been sought after and highly regarded in nearly every civilization in recorded history. From the Hope Diamond that was stolen from the collection of Marie Antoinette to Kate Middleton’s 18 carat sapphire that had originally belonged to Princess Diana, famous jewels through the ages have captured the imagination. Increasingly, those in the gem trade no longer use the terms precious and semi precious to classify gems. Since a new classification system has not been officially established, the following information on gems is presented using the traditional system.
Precious gems are almost always thought of as diamonds, rubies, sapphires, and emeralds. This is primarily a reflection of the quality and rarity of a gem.
From the mine to a glittering diamond ring, there is quite an extensive process that takes place. Those who sell diamonds will sometimes treat a less than stellar diamond with coatings and heat treatments to enhance the appearance. Cut, clarity, color, and carat determine the quality of a diamond. The price of rubies is primarily determined by the color of the stone. The most valuable rubies are what is called pigeon blood-red. Although most people associate sapphires with a rich, blue color, the gem actually can be found in nearly a dozen other colors. Emeralds are almost always found in shades of green. They are the softest of the precious stones and tend to break easily.
There are literally dozens of gems classified as semi precious. The following are a few of the better known semi precious gems. There are instances, however, when certain gems in this category are rare enough or of high enough quality that they are considered precious.
An amethyst is a type of quartz with hues ranging from pink to rich purple. Many of the amethyst gems on the market are heat treated to create a deeper color. Australia produces the vast majority of the world’s opal. Opal comes in a wide variety of hues, with blacks and reds being the most rare. Pure topaz is colorless, but often appears in a variety of colors because of impurities. Much of the topaz we find on the market has been heat treated to appear a dark blue. Tanzanite is considered more rare than diamonds because there is only one known source of supply. It is found in the hills near Mount Kilamanjaro.