What does 10K BA mean on a gold ring?

The marking "10K BA" on a gold ring indicates the following:

1. 10K: This refers to the gold purity, meaning the ring is made of 10 karat gold. Karat (abbreviated as "K") is a unit used to measure the purity of gold. Pure gold is 24 karats, so 10 karat gold contains 10 parts pure gold and 14 parts other metals, such as copper, silver, and zinc.

2. BA: This is likely an abbreviation for "British Association" or "Birmingham Assay," referring to the standards and assaying process that the ring has undergone. The British Assay Office, located in Birmingham, England, is responsible for hallmarking and certifying the purity of precious metals in the United Kingdom.

The "BA" marking indicates that the ring has been tested and verified by the British Assay Office to meet the required standards for 10 karat gold purity. It ensures that the ring contains at least 10 parts gold per 24 parts of the metal alloy, as per the regulations set by the British Assay Office.