PRECIOUS STONES AND GEMS-HOW ARE THEY VALUED
Some stones look as fragile as glass and are incredibly rare, but hey have an inherent strength. Stone Crystals may take millions of years to form, or may form as you watch. They may have been formed in rocks deep beneath the Earth’s surface, or they may be survivors of mountain building episodes or devasting volcanic eruptions, or they may have been washed into rivers and streams to be retrieved may be millions of years after their formation. These survivors are nature’s treat: perfect and brightly coloured crystals formed in dark deep rocks.
But for a gemologist, what are the special attributes of gemstones? For gemstones to be used in jewellery, ideally they should have three main attributes: beauty, durability and rarity. However not all gemstones possess all three. For example, some may be insufficiently durable (hard and tough) to use as a cut gemstone in a ring, but may be good for fashioning as a piece within a brooch, protected from damage by the mounting. Beauty and rarity have a direct impact on the value of a gemstone, the more beautiful and rare, the greater the price that will be paid.
Generally speaking, gemstones are minerals that have formed as sufficiently clear, large crystals that can be cut and polished foe use as pieces for personal adornment or objects such as sculptures, inlays etc. Precut gems and stones in matrix are also collectable. In addition to the mineral gemstones there are also other materials that can be used for adornment, such as pearl, Shell, Amber and other derivatives of plants and animals. These are called organic gems.
But not all gemstones are what they seem. A gemstone that has similar properties to a more valuable or rare specimen may be used to imitate it. Colour can be misleading: for example, at first sight colour of red spinel will be mistaken as Ruby. Glass, plastic and other materials both natural and manmade can also be used to imitate gemstones.
Synthetic gemstones have the same chemical and physical properties as their natural equivalent, but they are made in the laboratories. Part of the excitement of being a gemologist is to know how to use your eyes in order to distinguish the imitations, fakes and forgeries from the real gems.
