What does NG10k on gold mean?

NG is not a Standard Jewelry Abbreviation and it's possibly a maker's mark particular to New Generation Jewelry of Los Angeles.

Jewelry manufacturers and designers use maker’s marks or stamps that feature their logo, initials, trademarks, or company names to specify who made the jewelry. It provides proof that the jewelry item was made by the designer or jewelry maker and is considered "signed". These marks are registered by an Assay Office.

10K indicates the purity of the gold