Years ago I had a few of these and lots of their nail studs, had 4 gold studs with different colour stones, 2 different gold nails and also one that said maz with a cubic zirconia in, as they made special ones. They were held on by posts which had a thread and a tiny bolt, the pst went thru a hole in the nail and you had to spin it on and keep checking it so that it didn't come loose. I still have 2 silver ball stud rings that I managed to not loose, was very upset when I lived house and somehow the box all my nail jewellery was in vanished.
I meet the designers many years ago at one of the shows, I had a catalogue somewhere, will have a hunt but was years and years ago.