Carats in diamonds refers to a weight measurement. It was based on the carob seed which has a very regular weight. The unit of carats to measure stones was officially introduced in 1907. There are 5 carats in 1 gram. i.e. 1ct = 0.2g. Confusingly gold is also referred to in carats. Americans us the ‘ct’ as a weight measurement and ‘k’ to indicate carats as a ratio in an alloy. In South Africa we generally use ‘ct’ to indicate both weight and a ratio of alloy. The typical ratios of gold used in South Africa are 9ct, 14ct and 18ct. 24ct is pure gold. When you refer to 9ct you refer to a ratio of 9/24ths (a minimum of 9 parts out of 24) are gold in the alloy. 9 divided by 24 as a percentage is 37.5%, which is the amount of gold in the mixture. Gold jewellery is hallmarked to show the amount of gold in the mixture. Either the carat or the amount of gold over 1000 is used as the hallmark. 9ct= 375, 14ct= 585, 18ct= 750.
How do I keep my jewellery clean?Andrew2020-08-20T13:01:48+02:00
To keep jewellery looking like new is impossible if you plan on wearing it. You have to realise that the dulling of the jewellery is divided into different reasons and each reason has a different remedy
a)The metal scratches- You can use a polishing cloth with a small amount of success. The only real remedy is to have the ring professionally polished at a jeweller. Bear in mind that each time you polish a jewellery item a tiny layer of metal is removed. I would say that in normal conditions it isn’t necessary to polish an item more often than once a year.
b)The stone becomes duller with wear- This is the result of natural oils and hand-creams coating the back of the stone. All stones are influenced, especially paler coloured stones. Diamonds are least affected. Use an old tooth brush and diluted dishwashing liquid with luke-warm water. Make sure the plug is in the sink!
c)The metal discolours- This depends on the metal. If it is a white gold item then refer to the previous point regarding rhodium plating. If it is 9ct gold you have to realise that pure gold is chemically inert, but there is only 37.5% pure gold in 9ct. The atmosphere and specifically mineral rich liquids or household chemicals can react with the other metals in the alloy resulting in tarnishing. Silver naturally oxidises to form a black or brown layer on the surface of the silver. With both the 9ct and the silver problem you can either use a jewellery polishing cloth if the tarnishing is on the surface or you can use a jewellery cleaning liquid if the tarnish is in recessed areas. Make sure you read the directions on the liquid, most only require a few seconds of liquid and then rinsing with water. Using a brush with the cleaning liquid often helps.
Why is my white gold ring changing colour?Andrew2020-08-20T12:59:55+02:00
White gold is actually yellow gold that has been alloyed with different metals to make it whiter. 18k (18ct carat) gold is made up of 18 parts out of 24 parts gold. (24 carat being pure gold). The other 25% of the mixture is used to colour the metal or give it specific working properties. White gold is white, but with a hint of greyish yellow. Platinum on the other hand is purely white. White gold is plated with a white metal called rhodium (basically platinum), which makes a white gold and a platinum ring look identical at point-of-sale. But, the plating does rub away with wear. Depending on how rough the wearer is on the ring it normally takes 6 months to 18 months to be very noticeable. Some people don’t mind, but it definitely makes the ring look better and the diamond sparkle more when the ring is polished and rhodium plated. Platinum doesn’t have this problem.
Why are diamonds being quoted in dollars?Andrew2020-08-20T12:51:51+02:00
Diamonds are an internationally traded commodity similar to oil and gold, and as a result are priced in dollars. This doesn’t mean that only Americans buy diamonds, or that the price of diamonds is exactly the same around the world.