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Hallmarks Unless specifically exempted, all gold, silver and platinum articles offered for sale must be Hallmarked. A hallmark means that the article has been independently tested by an Assay Office and guarantees that it conforms to a specified legal standard of purity. This is called the fineness of the metal and the precious metal content is expressed as a millesimal number. For example, the number 999 means that the metal is 99.9% pure. The United Kingdom Standards of fineness are as follows: Gold (number stamped inside rectangular shape) Alloys of gold mixed with other metals, such as copper, silver, zinc. 375 - equivalent to 9 carat.Contains 9 parts of gold and 15 parts of other materials. 585 - equivalent to 14 carat. Contains 14 parts of gold and 10 parts of other materials. 750 - equivalent to 18 carat. Contains 18 parts of gold and 6 parts of other materials 916 - equivalent to 22 carat.Contains 22 parts of gold and 2 parts of other materials. 990 999 In the Victorian era 12 carat (500) and 15 carat (625) yellow gold were popular. Carat means the number of parts of gold out of a total 24 parts which are contained in a gold alloy. At the time of the Roman Emperor Diocletian, the gold coin known as a SOLIDUS had a weight equal to 24 "carat" seeds. From this idea developed of a measure of proportion by which 24 carats came to mean pure gold. Gold has many extraordinary properties: - It is a highly reflective metal. It has a lovely rich yellow colour. - It is virtually incorruptible. - Gold can be hammered out to the thickness of tissue paper to produce gold leaf. Gold is extremely rare. It is difficult and costly to extract from the earth. The rarity and the cost of mining and refining gold both contribute considerably to the overall price. White Gold is a mix of gold and silver or zinc or palladium. White gold was developed when platinum suppliers ran short during the First World War. White gold is not all that white in its raw state. It can be a sort of pale greyish yellow. To overcome this problem all white gold is given a thin surface plating of Rhodium. Silver (number stamped inside oval shape) Silver is mixed with other metals, chiefly copper. 800 925 - Sterling 958 - Britannia 999 Ancient people associated silver with the moon. Silver reflects light well and is a comparatively light metal. A disadvantage of silver is that it is easy to scratch, but it is easy to polish scratches out again. One characteristic of silver and its alloys is the tendency to develop a layer of black tarnish on the surface. This is a layer of silver sulphide and is caused by sulphurous componds in the air and in human sweat. Pure silver will tarnish less rapidly than standard silver. Tarnishing is usually easily removed by polishing. Brilliante Silver is a real innovation in precoius metals and is highly tarnish resistant. It contains 93.5 % silver along with zinc, tin, indium and copper. Platinum (number stamped inside house shape) 850 900 950 999 Platinum is a naturally white metal, but unlike gold it is used in jewellery in almost its pure form approximetly 95%. It is extremly long wearing and is very white, so its does not need to be rhodium plated like white gold does. It is a very dense and heavy metal, so a platinum ring will feel heavier that an 18ct gold ring. The name Platinum is derived from Spanish term "platina del Pinto", which is literally translated into "Little silver of the Pinto River". Palladium Palladium is a bright and naturally white precious metal. It does not require Rhodium plating. Palladium is a platinum group metal with a low specific gravity and melting point. Palladium is less expensive than platinum. Diamonds The name Diamond comes from the Greek word "ADAMAS" which means invincible. Most diamonds are fashioned in the Brilliant cut style. THE 4 'C's OF DIAMOND QUALITY: 1.CLARITY Refers to its optical quality. It is based on the size, number and visibility of any internal or external flaws or inperfections. It is from F(flawless) to P3 or I3(Pique or imperfect). 2.COLOUR Diamonds range from totally colourless through a progression of tinted and lighter colours to fully saturated Fancy colours. They range from Colourless (D) to Fancy coloured (Z+) 3.CUT Cut is the shape and style of the stone, as well as it's brilliance and light performance. 4.CARAT Carat is the Standard international unit of weight for Daimonds, Coloured Gemstones and Pearls. The carat is divided into Points, a unit of weight used only for diamonds 1 point = 0.01 carat Tanzanite In good quality the colour is ultramarine to sapphire blue, in artificial light, it appears more amethyst violet. Tanzanite is named after the East African state of Tanzania , which is the only country in which it is found.
Fire opal These stones tend to have one body of colour, the most common of which is reddish-orange, but they range from pale yellow to dark orange. Sapphire The gem is a variety of the mineral Corundum, which is the hardest mineral after diamond. The blue colour and the depth of this colour is caused by the presence and the amount of iron and titanium oxides in the mineral. Sometimes called "gem of the heavens". Persians believed that the earth rested on an enormous sapphire and sky reflected its beautiful blue colour. Pink sapphires occur in Sri lanka, Burma and East Africa. The colour varies from a very pale and delicate pink to a near-red. It is believed that if the stone is worn directly on the skin it will ward off ill-health and misfortune. Pearls Natural pearl Natural pearls are produced by oysters whitout assistance from man. By accident, an irritant penetrates an oyster, which the oyster gradually coats with layer upon layer of organic secretions to reduce the discomfort. The corect name for this layer is NACRE. The sheen seen on pearls is called orient. Cultured pearls Cultured pearls are produced by oysters farmed by man in warm waters. A cultured pearl is grown around a mother-of-pearl bead inserted by man into the oyster. Freshwater Pearls Freshwater pearls are grown in mussells instead of oysters, and can be an irregular shape. Imitation pearl They are made from beads coated with a substance derived from fish scales.
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