Gem” and “Jewels” redirect here. Rarity is another characteristic that lends value to a gemstone. A selection of gemstone pebbles made by tumbling rough rock with abrasive grit, in a rotating drum. Use of the terms ‘precious’ and ‘semi-precious’ in a commercial context is, arguably, misleading in that it deceptively implies certain stones are intrinsically more valuable than others, which is not pocket guide to crystals and gemstones pdf the case.
Gemstones may also be classified in terms of their “water”. This is a recognized grading of the gem’s luster, transparency, or “brilliance”. There is no universally accepted grading system for gemstones. Historically, all gemstones were graded using the naked eye. The GIA system included a major innovation: the introduction of 10x magnification as the standard for grading clarity. With modification, these categories can be useful in understanding the grading of all gemstones. The four criteria carry different weight depending upon whether they are applied to colored gemstones or to colorless diamonds.
In diamonds, cut is the primary determinant of value, followed by clarity and color. In gemstones that have color, including colored diamonds, it is the purity and beauty of that color that is the primary determinant of quality. Today such a distinction is no longer made by the gemstone trade. Many gemstones are used in even the most expensive jewelry, depending on the brand name of the designer, fashion trends, market supply, treatments, etc. Nevertheless, diamonds, rubies, sapphires, and emeralds still have a reputation that exceeds those of other gemstones. In general per carat prices of larger stones are higher than those of smaller stones, but popularity of certain sizes of stone can affect prices. 50,000 for a collector’s three carat pigeon-blood almost “perfect” ruby.