Random Riddle: Building Castles

They use me to build castles, but I’m not a brick.
They use me to make hands, but I’m not a finger.
I’m international, and cosmopolitan. I’m very often in Monte Carlo, Las Vegas, Atlantic City and even in Punta del Este.
I’m not alive but I have 81 hearts.

What am I?
 

Random Riddle: Building Castles