Below you will get a quick overview about the different materials and how it looks like (not to scale).
Solid gold jewelry is the highest quality gold jewelry you can find, as it does not discolor or tarnish with repeated wear. Unlike plated, vermeil, or filled jewelry, solid gold jewelry can be worn daily for decades without tarnishing. Solid gold jewelry is classified by a number and a "K", which stands for karat. As an added benefit, solid gold jewelry increases in value over time, and is a true investment you can wear!
Gold filled jewelry is created by pressure bonding an actual thicker layer of 14k gold to another metal, usually brass or copper. In the US, the gold content for gold filled jewelry is required to be at least 5% of the total weight. Although a gold filled piece of jewelry is not solid gold, it has the same desirable properties and look of solid gold.
Gold filled jewelry will last longer than plated or vermeil. It won’t tarnish and the gold layer will not rub off. Those with sensitive skin can wear gold filled without worries of an allergic reaction. Gold filled jewelry can be worn even daily without fear of fading or tarnish for many cases as long as 30 years with proper care.
While the process is similar to gold plating, the underlying materials used in gold vermeil jewelry is sterling silver. The silver is then gold coated at a thickness of 2.5 microns. Gold Vermeil is the perfect option for those with metal allergies due to the durable thickness of the gold combined with the base of sterling silver.It's more affordable than solid gold and gold filled and a lot more durable than gold plated. Gold vermeil jewelry may last longer than gold plated jewelry, but will eventually wear off.
Gold plated jewelry is the cheapest to produce and the least durable. Gold plated jewelry is made by using electricity to deposit and bond a very thin layer of gold over a low cost material. Gold content in jewelry made using this method is less than 1%. Due to the low level of gold used, it wears off quickly over time and the underlying materials can sometimes turn your skin green.