21k gold ring update

[Heavygold4me]

So I’ve been going back and forth on whether or not this ring is gold or gold plate. I did a specific gravity test and came up with high 10 karat, assuming I did the test correctly. Did a deep scratch with a triangle file and thought I saw a difference in the color and thought it must be heavy gold plate. The manufactures website says they specialize in high end plated jewelry.
All that being said I have a friend who owns a pawn shop and had him scan it today, it came up as 20k gold. So I’m counting it as gold based on the scan.