Gold is one of the most precious metals available, and its use in jewellery is obviously common. But there are some things to be aware of:
- Gold is usually bought and sold on the market in troy ounces, not the usual everyday avoirdupois ounces. In gram terms, a troy ounce is 31.103 grams, but an avoirdupois ounce is 28.34 grams. So if you are going to buy an ounce of gold make sure it's a troy ounce; or you stand to lose about 10 per cent of the price.
- Gold purity is rated in karats (abbreviated to k, or ct). Pure gold is 24 karat. Commonly available purities are: 9ct (37.5 per cent pure), 18ct (75 per cent pure), 21ct (87.5 per cent pure) and 24ct (99.99 per cent pure).
- Pure gold is too soft to be used for jewellery. The highest purity gold used for jewellery is 21ct, but it's fairly uncommon; 18ct is far more common; 9ct is most common of all because it's cheapest.
- Gold differs in colour, depending on what's being used to make up the rest (usually a mix of silver, copper and zinc). They include yellow, white, green and pink (also known as rose'). Tem42 describes them nicely under his gold writeup. Not only is it best not to mix different colours of jewellery, it is best not to mix different purities; so 18ct yellow gold and 9ct yellow gold are slightly different colour.
- Rings come in sizes from A to Y; depending on the diameter of the finger. Expect to pay a little extra for sizes T and above.
- If you go to a jeweller, and you have a particular idea for a ring; you can sit down and design a ring with them. You don't need to stick to what's in the shop window, and it's not always more expensive.