The first section is in a Q&A format and the next section is a very short essay.

What is the difference between 18 and 9 carat gold?

Gold is a pure metal but it is inherently soft, therefore to make it into practical jewellery it must be alloyed with other metals to make it harder. Pure gold is known as 24 carat or 1000 parts pure. 18 carat gold is a high purity gold alloy of 750 parts gold per 1000 (75%). 9 carat gold is a harder gold alloy of 375 parts per 1000 (37.5%), this is the minimum British standard. It is illegal to describe an article as gold if it falls below this standard.

thought gold was yellow, so what is red or white gold?

Pure gold, i.e. 24 carat is yellow, but as gold used in jewellery production is an alloy (see previous question) it is possible to change the colour balance by introducing certain metals. White gold will contain proportions of palladium and silver, red gold will contain a proportion of copper. The purer the carat of gold the less colour change is possible. Therefore 18 carat gold will always be more yellow than 9 carat gold.

Why has my white gold engagement ring dulled over the years?
Normal wear and tear will result in fine surface scratching building up which can soften the shine of all precious metals. With white gold however it was inevitably rhodium plated as a final finish before being offered for sale. As this is a thin electroplated finish, it will deteriorate over time especially in high friction areas for example where it abuts another ring.

What is rhodium and rhodium plating?

Rhodium is a very white metal in the same group of metals as platinum and palladium. Electroplating will deposit a thin layer of metal on the surface of the host metal; this is measured in microns and will wear away in time, revealing the host metal beneath. In jewellery production it is used extensively as an electroplated surface finish, giving a whiter look to a white gold ring, or to highlight an area like a setting. It is rare to find a white gold ring in a jewellery shop which has not been rhodium plated. Unfortunately not all retailers tell their customers this fact, and incredibly some retailers do not know that their white gold has been rhodium plated or even know about this process.

OK but can I have my shiny white ring back again?

The good news is yes. The ring or item of jewellery will need to be carefully re-polished by the maker or skilled repairer, and then rhodium plated once again. However the question perhaps should be asked, do you want this whiter than white gold look or would you be happy with the natural finish of the white gold? Bear in mind that a higher carat white gold ring will be naturally more yellow than its lower carat counterpart.

Should I order a white gold ring which has been rhodium plated?

This is a thorny question which is why most jewellery retailers conveniently ignore it, however we believe it should be an issue which the jewellery industry engage in, for the sake of transparency for the customer. The opinion of Welded Bliss is that precious metals of any type should be sold without the adornment of electroplated finishes, whose sole purpose is to create the illusion of a colour which is not the colour of the metal being sold, unless so requested by the customer. This of course also applies to rhodium plated silver and platinum as well as gold plating e.g. to make lower carat gold's appear deeper yellow. In any event we believe it contravenes at least the spirit of normal trading standards, unless this finish is stipulated at the point of sale. Our policy therefore is to supply white gold in its natural state unless the customer requests a rhodium plated finish. 18 carat white gold could be described as soft white or pale yellow while 9 carat gold will be whiter.

What is the meaning of carat?

Apart from not being a vegetable. The word carat has two distinct meanings. In relation to gold, carat refers to the purity of the metal, e.g. 24 carat (pure gold) or 18 carat etc. Please also see question one. In relation to gemstones especially diamonds, carat is a measurement of weight. One carat is 0.2 grammes, a carat can be split into 100 points, therefore a half carat diamond may be described as a 50 point stone, and this would weigh 0.1 grammes. Carat is often mistaken for size. It is usually possible to determine the approximate carat or weight of say, a good brilliant cut diamond by its diameter, however old or antique cut diamonds are much harder to guess by size alone.

British gold

The first compulsory hallmark in London (the leopard head) was introduced in the year 1300 and a compulsory maker's mark in 1362. The date letter (originally known as the assay master's mark) was introduced in 1478 along with the necessity to have items stamped independently at the Goldsmith's Hall, hence the name 'hallmark'

15, 12 and 9 carat standards were first introduced in 1854 in response to the demand for watch cases for the American market. 15 and 12 carat standards were withdrawn in 1932. The four standards of 9 (375), 14 (585), 18 (750) and 22 (916) carat remained and 2 new standards of 990 and 999 have more recently been introduced.

All items of gold which weigh over 1 gram must be hallmarked according to British law. This hallmark is impressed on the piece at one of the British assay offices... today only London, Birmingham, Sheffield and Edinburgh. All British hallmarks must include the following separate marks: The maker's or sponsor's mark; fineness, purity or control mark (e.g. 375 for 9 carat); assay or town mark (e.g. the anchor for Birmingham). Other marks e.g. date letter are now optional.

Hallmarks are usually applied to the jump ring in order not to damage the charm. Lighter weight articles under 1 gram e.g. Italian hollow or (fused stampings) may not have hallmarks, but may be marked 375, 750 etc.