I have an "H" with another mark inside an oval on my gold plated 925 diamond pendant. What does it mean?

by Samantha Ray
(Springfield, Ohio)

I got ahold of a gold plated, 925 sterling silver & diamond pendant. I made sure it was real diamonds by going to the jewelers. They confirmed diamonds were real, however, didn't give any more details on it. On the bail, it says 925. Next to that, it has an "H" with another mark I can't identify inside an oval like. I have a jewelers loupe but I still can't figure it out! !LOL>.. The pendant is a four leaf clover shape. I will try to get best pic I can of the stamp. I also bought a larger four-leaf clover that was stamped with same symbol. What do I have? TY