The Difference Between Minerals and Gems

When you see the beauty of a cut diamond or a brilliant ruby, it may be obvious to your eye that you are looking at a gem. What is it, though, that defines the difference between an ordinary mineral and a gem?

The separation between mineral and gem really is partly defined by historical use. In common usage, a gem is really any nonmetallic mineral that is used in jewelry. Fewer than a hundred minerals are classified as gems today, and some material known as gemstones are not really stones. For instance, pearls are commonly called gemstones even though they come from oysters. Amber, although often referred to as a gemstone, is sap which has become fossilized. Coral is often referred to as a gemstone when used in jewelry, although it is the remains of skeletal material of a sea creature.

There once was a greater division between those stones defined as "precious" or "semiprecious." These terms were dependent on the rarity of the gem and its natural beauty. When the ability to manufacture diamond crystals in a lab first appeared in 1955, the division became more blurred, although the rarest gems are still the most highly desired and valuable. Value will also diminish or increase depending upon the fashion of the era.

Minerals are also classified as gems dependent on their strength and durability. A common mineral that is easily broken will naturally not be chosen for use in jewelry. The basic structure of minerals and gems is very much the same, however the crystalline quality of the mineral does not have the same strength or clarity as that of the gem. This normally has to do with the geological process that has occurred upon the mineral. For example, the best diamonds are produced by the correct amount of heat and pressure. There has to be the right combination of carbon and gas present to create a valuable and durable diamond.

Gem and mineral shows quite often feature displays illustrating how the geological material is formed. Next time there is a show in your town, make a point of attending and seeing the sometimes subtle difference between gems and ordinary minerals.