We can decode fairly easily, these marks: *750 FOMO 66 PD* on bracelet near clasp.
You mention in your post, the bracelet is vintage and was purchased at auction.
1. *750* = 18k gold. This is the European standard. `750` = 75% pure gold. 2. *FOMO* = Maker’s mark. This is likely *Fratelli Monzio Compagnoni* or another Italian maker. Italian makers often used 4-letter marks. 3. *66* = Model / size / batch number. Italian bracelets often had this. 4. *PD* = This is the key. `PD` = *Palladium*. This means the white parts of the bracelet are 18k white gold alloyed with Palladium instead of Nickel. Very common in high-end Italian/European jewelry from 1970s-2000s.
Your bracelet is 18k gold - the '750' confirms that.
'FOMO' is the Italian maker's mark. 'PD' means Palladium white gold, so any white sections are 18k as well. '66' is likely a model or batch number.
So you have a vintage 18k Italian bracelet, with palladium white gold accents. A nice find from auction!
