information about cutting gemstones
information about cutting gemstones :-
in order to show off the best qualities of a gemstone it must be cut and polished .
the best minerals for jewellery are hard and so special materials must be used to cut and polish them.
in the case of rubies and sapphires carbcorundum an artifical silicon carbid can be used.
but the only material which can cut and polish diamod is diamond itself .
the chief aims of a lapidary (or gem-cutter) are to remove all flaws make the best use the mineral soptical qualities waste as litttle of the specimen as possible and in the case of clloured minerals to achieve the best colour .
to get the best optical qualities from a transparent gemstone the lapidary must cut a series of facets(inclined surfaces )on the top and bottom of the stone .
if the facets are the right size and shape and cut of the gemstone .
particularly in the case of the diamond the facets also disperse light producing a play of colours called fire .
skilled lapidaries use several methods of cutting some of which were specially developed for particular gemstones .
the step or trap cut has parallel facets across the top and bpttom .it is also calledthe emerald cut because it is often used for that gemstone as well as aquamarines tourmalines and so on .
sometimes gemstones such as sapphires are given a brilliant top but a step cut bottom .this is called a mixed cut .
another cut used for small diamonds paropes ( ruby -red garnets)and other syones is called the rose cut .this has flat bottom but the top has 12 or 24 facets which end in a central point giving the stone a shape like a hemisphere .
it is used for a wide variety of gemstones and is particularly sutable for opaque minerals and those that contain fibrous structures such as tiger s eye.
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