Very nice find! It reminds me of a Japanese Damascene mark I've seen off and on,but not quite the same. Wish I could be of greater assistance. If I turn green with envy, would that help?
Absolutely, the markings are spot on. Of course I've certainly seen a number of fakes. If you follow this site, you are no doubt aware you can get it tested at any number of places for free.
I don't know the maker but here is a pair of earrings with the same mark, they say it says HK below the markings. I can't see it good enough on their photo to tell either. Their earrings are silver in color though, not gold.- VINT 30'S SIGNED JF( L IN TRIANGLE)H.K. BASKET EARRINGS