Jewellery Materials & Manufacture

Of the wide range of materials used for making jewellery, metals are the most common constituent. The metals used range widely from inexpensive alloys (like stainless steel) for budget jewellery, to the expensive precious metals (like gold, silver, platinum, titanium, and palladium) for higher end jewellery. In the case of gold jewellery, gold alloys are used of varying purity as indicated by the number of karats (displayed by the letter K), where the higher the karat, the higher the purity, and the more valuable the jewellery item. A minimum of 9 karats (9K), equivalent to 37.5% pure gold, is required for jewellery to be legally classified as gold. Furthermore, the number of karats usually increases to 18K, equivalent to 75% purity; any higher and the gold is considered by many to be too soft to be suitable for use in jewellery. Nevertheless, jewellery containing higher purity gold (up to 24K) is available. In the case of silver jewellery, sterling silver is most commonly used. Plating less expensive alloys with a thin layer of gold, silver, rhodium or other precious metals is popular for many jewellery items in order to offer an attractive appearance for a fraction of the cost when compared with using the same precious metal in solid form.

Precious metal jewellery (such as gold, silver, and platinum jewellery) may be finished by a variety of techniques, of which high polished finishes are the most popular. Other finishes include satin (otherwise known as matte), brushed, and hammered finishes. Whilst the shine of a polished finish gives precious metals a more attractive and glamorous appearance, a satin finish may be preferred for some items of jewellery in order to highlight and accentuate the gemstones. Brushed and hammered finishes give the metal of jewellery various kinds of textured appearances.

The metal component of jewellery usually forms the structure of the item. Where gemstones are incorporated within jewellery, they are typically set into these metals. Other materials used in making jewellery include glass, including fused-glass or enamelled glass, shells and other natural materials, wood, and clay. Such materials are presented in the form of beads in the case of beaded items of jewellery, including beaded necklaces, rings, earrings, and bracelets. The glass component of some jewellery can take a variety of forms through advanced glass making techniques. Examples include enamelled glass (smalto), crystalline glass, gold-threaded glass (goldstone), multi-coloured glass (millefiori), and milk glass (lattimo). Glass may even be manufactured to imitate gemstones in some jewellery to achieve a similar visual appeal at a fraction of the cost of using real gemstones. This leads on nicely to considering the types of gemstones used in jewellery. Gemstones are precious and semi-precious stones with attractive deep colours making them a popular component of many types of jewellery. Gemstones may be grouped into one of two categories, namely organic gemstones and inorganic gemstones, with the latter being the most common and wide ranging. Organic gemstones are produced by living organisms, whereas inorganic gemstones are formed from natural minerals. The most common gemstones used in jewellery are amber, amethyst, emerald, jade, jasper, quartz, ruby, sapphire, and turquoise. Let us consider each in more detail:

Amber

Amber is an organic gemstone formed by the hardening of tree resin over long periods of time. Whilst amber can be as old as a hundred million years, the age of the gemstone must be at least one million years old for it to be classified as real amber.

Amethyst

Considered the most valuable gemstone in the quartz family, Amethyst is an inorganic gemstone with a beautiful and distinctive purple colour ranging in tone.

Emerald

Treasured throughout history and representing one of the three main gemstones (alongside sapphires and rubies), emeralds are inorganic gemstones with a colour in the range between light green and green-blue.

Jade

Known as the stone of heaven, jade is an inorganic gemstone which may exist in a variety of colours with green being the most common. Jade gemstones are very much associated with Asian culture and tradition.

Jasper

The Jasper gemstone exists in a variety of colours often with unique, random patterns and swirls. These characteristic patterns are particularly evident in a type of jasper known as picture jasper, which has a distinctive beige-brown colour. Jasper is a member of the chalcedony family of gemstones.

Quartz

Quartz consists of a group of crystalline gemstones displaying a variety of colours. Common examples include rose quartz which displays a distinctive pink colour, smoky quartz which exists in a range of brown or beige shades, and rutilated quartz which features characteristic needle-like inclusions. Various other gemstones, including amethyst and citrine, belong to the quartz family of gemstones.

Ruby

Highly treasured throughout history, rubies are among the most precious of all gemstones with regard to their value and appeal. In fact, the word for ruby was ratnaraj in ancient India, interpreted as the king of precious stones. The characteristic colour of rubies is an intense red.

Sapphire

Sapphire represents one of the three main precious gemstones (along with emerald and ruby), whilst being the least expensive. The most common type of sapphire is blue sapphire with a typical blue colour of variable intensity. The gemstone can however be found in a range of different colours.

Turquoise

Found in a few exclusive areas of the world, turquoise is a popular gemstone used in various types of jewellery, and has a blue-green colour which ranges in intensity, in some cases with brown graining.