I would surf the internet or when you go to a jewllrey shop or something like that ask a person who works there i bet they would know! :)
10k, means the earing stud is made of 10Karat Gold.
Usually this stamp appears after 10K and means it is gold plated and not solid 10k gold. means W ith B onded gold.
10K yes it is gold. IBG= Ira B Goodman jewelry maker (makers mark)
If the 'B' comes before the 10k it's a maker mark, after the 10k it's gold over something else. I have a gold ring marked ( B10k ) it's real 10kt I've been wearing it for years now and no change. But mine is Victorian pretty old.
The "b" could be an initial of some sort but has nothing too do with value of the gold.
What does it mean
It is most likely the stamp of the manufacturer
these are the proper hallmarks 24 Karat Gold - 24K or 999 22 Karat Gold - 22K or 917 21 Karat Gold - 21K or 875 18 Karat Gold - 18K or 750 14 Karat Gold - 14K or 585 10 Karat Gold - 10K or 417 9 Karat Gold - 9K or 375 14 Karat Gold filled - 14K GF or 14K/20 Sterling Silver - 925 Pure Silver - 999 the ratio is A/24=B for example 10/24=0.417 therefor 10K=417
What does b 18k mean
If you see the imprint of "B 25" stamped on a ring, the "B" most likely represents a specific date. The "25" represents the quality of the gold or the karat.
The b in 14 KB is where the gold came from in your case it is from Mexico.
The price of a stamp went from 15 to 18 cents. So the face value of the B stamp is 18 cents. The B make up stamp would be worth 3 cents.
10K gold is 10 parts gold to 14 parts of ... some other metal (usually mostly silver with some copper,nickel, and/or zinc). The reason for using gold alloys rather than pure gold in jewelry is that a) other metals are cheaper than gold and b) the alloy is considerably harder than pure gold, so it stands up better to wear and tear. It is possible to refine 10K gold to pure gold, if that's what you're asking, but the easiest way involves strong acids, so you may just want to sell it as is to a professional refiner.