Gold is undeniably one of the world's most precious metals, and may well be the first metal known to man. It is remarkable that all of the races of mankind have selected gold as the first and chief representative of value. In the earliest times it was used as a medium of exchange in the form of bars, spikes and rings; as well as being used from a very early period for the construction of personal ornaments. Gold can be found anywhere; it exists in plants, rivers, oceans, mountains...however, it is extremely difficult and costly to extract just one once of pure gold.
The universal use of gold preference to all other metals is due to its many properties; its colour and luster, its malleability and its indestructibility. Gold does not tarnish nor can it be destroyed. it may be reduced to a liquid and the liquid transferred to a powder, and the powder when melted in a crucible returns to its natural state.
Gold has long enjoyed unsurpassed popularity as a medium for fine jewellery. There seems to be no end to the range of colours, finishes and styles available and gold remains a perennial favourite for gemstones.
Buying Gold Jewellery
Pure gold means 24 carat (24ct) gold, the metric equivalent being 1000. Because 24ct gold is too soft for all ordinary purposes, it is generally mixed with other metals to increase its hardness and durability. Silver and copper are the principal alloys used, although iron is used in small quantities for different purposes.
The carat quality marking tells you what proportion of gold is mixed with the other metals. 18ct (750) jewellery contains 75% of pure gold, mixed in throughout with 25% other metals known as alloys. The higher the carat rating, the higher the proportion of gold in the piece of jewellery. When purchasing a piece of gold jewellery, you should always look for the carat mark which should be stamped on it. Some of the common markings found on jewellery, with their metric equivalents are:
- 22ct or 916
- 18ct or 750
- 14ct or 585
- 9ct or 375
Solid gold refers to an items made of any carat gold, if the inside of the item is not hollow. The proportion of gold in the piece of jewellery still is determined by the carat mark.
Jewellery can be plated with gold in a variety of ways. Gold plate refers to items that are either mechanically plated, electroplated, or plated by any other means with gold added to a base metal. Eventually, gold plating wears away, but how soon will depend on how often the item is worn and how thick the plating is.
Gold-filled, gold overlay and rolled gold plate are terms used to describe jewellery that has a layer of at least 10 carat gold mechanically bonded to a base metal.
Gold electroplate describes jewellery that has a layer (at least .175 microns thick) of a minimum of 10 carat gold deposited on a base metal by an electrolytic process. The terms gold flashed or gold washed describe products that have an extremely thin electroplating of gold (less than .175 microns thick). This will wear away more quickly than gold plate, gold-filled or gold electroplate.
Colours of Gold
Gold is available in different colours - most commonly yellow gold, white gold and rose gold. Jewellery may also be made using a combination of gold colours - two-tones, three-toned, multi-toned. The difference in colours is determined by the metal components in the alloy mix. Yellow gold is made by mixing pure gold with alloy metals such as copper and zinc. Rose gold is made using a mix which includes a larger proportion of copper - providing the reddish-rose colour. As the colour difference is due to the metal components in the alloy mix, the colour of yellow gold and rose gold will not chip, fade or wear off with age.
White gold is an alloy of gold and some white metals such as silver and palladium. The natural colour of white gold is actually light grey. White gold can be coated with another white metal called rhodium. Rhodium is a metal very similar to platinum and shares many of the properties of platinum including it's white colour. Rhodium plating is used to make the white gold look more white. The rhodium is very white and very hard, but it does wear away eventually. To keep a white gold ring looking its best it should be re-rhodium plated approximately each 12-18months.