Value: Usually the cheapest option. Contains real gold, but very little (about one gram of real gold in one pint of solution can be used to plate thousands of pieces!). Cheaper jewelry will have a very thin plating which wears off fast, but some higher quality brands will have a thicker plating with an additional protective coating to help it last longer.
How to find: Will have no quality mark on the jewelry, but may have company name/logo stamped.
Gold-Plated over Sterling Silver
Value: Still gold plated metal, but with valuable sterling silver. Sterling silver is a sought-after material ($0.57 per gram*) while still being very affordable compared to gold ($43.40 per gram*). The gold plating will wear off with time, but the silver underneath will not tarnish or cause skin discoloration for most people.
How to find: Will be stamped "925" or "sterling," can also have company name/logo stamped.
Value: Has 5% of the value of solid gold. To be called gold-filled by U.S. law, the plating needs to be very very thick (at least 5% of jewelry total weight). Great to wear (the gold will never wear off!) but bad as an investment (has low re-sale value).
How to find: Will be stamped "1/20 14k" (meaning 1/20 of total jewelry weight is 14k gold), can also have company name/logo stamped.
Value: The real deal. Solid gold is the best metal for wearability and as an investment. Pure 24k metal cost is $43.40 per gram, 14k metal costs is $25.32 per gram.*
If you are not sure what kt means, here's a handy guide that explains the meaning behind 14k.
How to find: Will be be stamped "10k" or "417", "14k" or "585", "18k" or "750", "24k" or "999." If the piece is stamped “18k 925” it means it is made of both 18k solid gold parts and solid silver parts.
Solid gold can be any color - yellow, rose or white.
Value: Hollow gold is still gold but with empty space inside the jewelry piece, so it still has the same value by weight. Hollow gold is used to make jewelry both lighter and cheaper, and is very common with bangles and hoop earrings. By U.S. law, companies should disclose when a jewelry piece made of hollow gold. It may be described as hollow, tubed, semi-solid, etc.
How to find: Will be stamped the same way as solid gold.
* prices for raw metal, prices change everyday. The silver calculated at $18/oz and gold at $1350/oz market for Jan 2018.