This is a fact that has yet to change: while there is a universally accepted grading system for determining the value of diamonds, a system has yet to be made for classifying colored stones. The Gemological Institute of America (GIA) developed a grading system for diamonds in the early 1950s. Historically, however, all gemstones were graded using the unaided eye. The GIA system though, included a major innovation-the introduction of 10x magnification as the standard for grading clarity. Assuming the jeweler has perfect vision, other gemstones are still graded using simple examination. For the past several hundred years, gemstones have been broken down into two categories. Some are classified under the precious type and others are categorized as semi-precious. They make for great centerpieces in colored stone jewelry. Though today we think primarily of diamond, ruby, sapphire and emerald as "precious", these categories are based mainly on fashion demands and the composition of these two lists have constantly evolved over time.