Beware of the pitfalls when wanting to purchase or sell ANY item described as GOLD. To be named and promoted as 'gold' (in most countries of the world) it must be a solid gold construction and so marked:
There are various markings both current and older (now unused) The markings are of two types. In North America we use: 10 karat, 14 karat, 18 karat and 22 karat. These MUST be stamped on the item, with the manufactures logo or name ! There are short forms for 'karat' as: 'KT' or "K' In Europe they use the metric % which is older and accurate too. 10 kt is 375 14 kt is 485 18 kt is 750 and 22 kt Historically there was also 9 kt (used in the UK) and 15 karat
The metric % is very good as it indicates the % of gold to the alloy used therein.
The term 'solid gold' is accurate being 10 kt, 14 kt etc.
The fact is the term pure gold..means just that. It is very very rare so do not use the term. Even gold coins have some alloy, usually being 22 parts pure gold to 2 parts alloy.
To understand that back in time, someone decided that pure gold would be divided into 24 parts, or sections, (whatever)
Therefore 14 karat would be 14 parts pure gold to 10 parts alloy mix. (think chocolate cake, at 90 % white cake mix to 10 % chocolate, giving the color and taste) To be aware then think metric %
The so called gold plating is very ambiguous and it is were the problems arise. To editorialize: "I recently looked to buy a watch bracelet, the seller described it a solid 18 kt....however it was not, It was electro- plated with a thin layer of (likely) real 18 karat gold, but the layer is so thin one could cut a cross section & be unable to measure it. It wears off very quickly.
True rolled gold plate (RGP), and that is the term was/is made by fusing a layer of say 14 kt solid gold to a base metal, usually copper. It must measure 1/10 of the total thickness (it can be distrubuted partially on the front and back) It was common for watch cases & sometimes they called it : 10 year warrenty. It must be so marked with the Mfg logo or name.
True Gold filled (GF) was the same method but must be twice as thick or 1/5 (or 1/20)
The Europeans used and electo plating method but allowed it to build up the equivelet of RGP or GF and they called it micron. The micron layer to match RGP was '20' and '40' for Gold filled ! Note: I can be corrected on these #'s Editorial: I notice that a lot of new and very expensive watch brands use 3 or 5 micron ! Most sales clerks do not know or understand, I can never get a proper answer from them & it is very frustrating. These layers will wear off quickly.
There is more detail available, this is presented as a 'quick overview' but please try and understand and comply. We must end the errors that occur in 'gold' listings PS: gold is spelled 'karat' ONLY with a 'K' Carat with a "C" is gem weight ! Do not err.