There are 4 types of gold jewellery/Watches available, I will explain each one in order of best quality first.

1. Solid Gold: Exactly what is says, comes in 9k (although this is only recognised as “gold”  in the UK), 10k, 14k, 18k and 24k Sometimes other denominations like 19k & 20k but these are scarce.

 2. Gold Filled (GF): GF is a thick plate of solid gold bonded through heat and pressure to a base metal (commonly sterling silver but can be any alloy), this gives it the look and feel of solid gold and is the next best alternative as it wears very little. It's most common form in 10k and 14k. Gold filled wrist bands almost always have a stainless back.

3: Rolled Gold (RG/RGP). This is also plate of gold, again bonded to metal this time through high pressure "rolling". It was most common in 10k, 12k but sometimes found in 14k. Has a thinner layer than GF.

 4: Modern Gold Plate(electroplate):  EP is in essence a gold wash with very low gold content and very susceptible to wear, this doesn't usually show a gold content as it is too low or measure it in microns(thickness).