Jun 07, 2015 Gold. What you should know about it. Gold is a natural element with a chemical symbol 'Au'. Its purity is measured in Karats -not to be confused with Carats, which is a size/weight measure for gemstones. ( more on that later). In its purest form, gold has 24 karats. It is 99.99 % pure. As an investment it is usually sold at this level of purity -whether as coins, wafers or bars. All other karats of gold are fractions of pure gold. Common industry examples include: -18k , ( 18/24ths ) which is 75% pure gold. The remaining 25% are alloys (other metals). It is usually marked as 18k, but can also be stamped "750" ( parts per 1000 ) -14k , ( 14/24ths ) which is roughly 58% pure gold with the remaining 42% are alloys. It is usually marked as 14k, but can also be stamped "585" ( parts per 1000 ) -10k , 10/24ths ) which is roughly 42% pure gold with the remaining 58% being alloys. It is usually marked as 10k but can also be stamped "416" ( parts per 1000 ) You will also find other karats of gold -such as 9k, 12k, 20k, 22k which vary in popularity according to a country or part of the world it is sold in. Alloys are any 'recipes' of metals that are combined with gold to give it a particular colour or property. ( red gold, white gold, yellow gold, green gold etc ) Typical alloy metals include ( but aren't excluded to ) copper, silver, zinc, nickle and platinum. Gold-fill : Some jewellery is sold as "gold-fill" and it decreases the cost of a chain, ring etc substantially. It is essentially a thin covering of gold over a base metal such as brass of silver. In appearance it looks identical to karat gold. A 14k gold-fill chain for example, will have at least 1/20 of the weight of solid 14k, so there is not a lot of gold on it but it will have the appearance. Over time ( usually a few years ) the gold will begin to wear off and expose the metal under it. One shouldn't think about selling gold-fill for scrap. There just isn't enough to recover. Gold plate is the same idea as gold-fill but with even less gold content than gold fill. Gold scrap is solid karat jewellery that is no longer useful or wanted and purchased for re-melting and refining. Its value will vary from one day to the next depend on the international markets, which are in a constant state of flux. Scrap gold is sent back to a refiner to remove the alloys and convert it back to a pure state (24k) and the cycle begins anew. Perhaps next to water, gold is the most re-cycled element on our planet. ( Don't throw broken chains, rings etc in the garbage ! -Yes, it's been done before ) ...and yes, I purchase scrap gold & silver.