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Gemstones are sometimes called precious or semi-precious stones, though the terms are not always directly relevant to the stone’s monetary value. In fact, the types of rocks that have been considered as a true precious stone has actually changed a little throughout history and in different regions of the world. Today, it is commonly agreed that diamond, ruby, emerald and sapphire are the precious stones and all others are semi-precious.
At the very basic level, there are two distinctive groups of gemstones: mineral gemstones and organic gemstones. Mineral gemstones include the majority of rocks we think of when thinking of gemstones; agates, amethysts, diamonds, jade, jasper, quartz and many others are all mineral gemstones. Some organic gemstones are amber, copal, coral, pearl and abalone.
The quality and value of a stone is determined by many factors. One factor is hardness which is measured on the Mohs scale. This scale measures scratch resistance to determine the hardness of a stone. Another factor that determines a stone’s quality is its clarity. An unusual marking in the stone with colors or a star effect that is called an asteria also determines the stone’s value.
Man’s ability to replicate many gemstones has greatly improved over the years. In fact, some man-made stones can match or be of superior quality to natural stones. This is great since some gemstones are used for other items besides jewelry. For instance tiny pieces of diamond are used on abrasives. The stones are man-made so they aren’t using up natural resources.
