Most American and European gold jewellery is made of an alloy of gold, the purity of which is stated in karats, indicated by a number followed by the letter K. American gold jewellery must be of at least 10K purity (41.7% pure gold), (though in England the number is 9K (37.5% pure gold) and is typically found up to 18K (75% pure gold). Higher purity levels are less common with alloys at 22 K (91.6% pure gold), and 24 K (99.9% pure gold) being considered too soft for jewellery use in America and Europe.

The word jewellery is derived from the word jewel, which was anglicised from the Old French "jouel" circa the 13th century. Further tracing leads back to the Latin word "jocale", meaning plaything. Jewellery is one of the oldest forms of body adornment; recently found 100,000 year-old beads made from Nassarius shells are thought to be the oldest known jewellery.

Sapphire: The most popular form of sapphire is blue sapphire, which is known for its medium to deep blue colour and strong saturation. Fancy coloured sapphires in various colours are also available. In the United States, blue sapphire tends to be the most popular and most affordable of the three major precious gemstones (emerald, ruby, and sapphire).

Materials and methods:In creating jewellery, gemstones, coins, or other precious items are often used, and they are typically set into precious metals. Alloys of nearly every metal known have been encountered in jewellery -- bronze, for example, was common in Roman times. Modern fine jewellery usually includes gold, white gold, platinum, palladium, titanium or silver.

Beads are frequently used in jewellery. These may be made of glass, gemstones, metal, wood, shells, clay and polymer clay. Beaded jewellery commonly encompasses necklaces, bracelets, earrings, belts, and rings. Beads may be large or small, the smallest type of beads used are known as seed beads, these are the beads used for the "woven" style of beaded jewellery. Another use of seed beads is an embroidery technique where seed beads are sewn onto fabric backings to create broad collar neck pieces and beaded bracelets.

Brushed finishes give the jewellery a textured look, and are created by brushing a material (similar to sandpaper) against the metal, leaving 'brush strokes'. Hammered finishes are typically created by using a soft, rounded hammer and hammering the jewellery to give it a wavy texture.

More recently, the display of body jewellery, such as piercings, has become a mark of acceptance or seen as a badge of courage within some groups, but is completely rejected in others. Likewise, the hip hop culture has popularized the slang term bling-bling, which refers to ostentatious display of jewellery by men or women.

Silversmiths, goldsmiths, and lapidaries methods include forging, casting, soldering or welding, cutting, carving, and "cold-joining" (using adhesives, staples, and rivets to assemble parts).Diamonds:Diamonds were first mined in India. Pliny may have mentioned them, although there is some debate as to the exact nature of the stone he referred to as Adamas; In 2005, Australia, Botswana, Russia and Canada ranked among the primary sources of gemstone diamond production.