11ct Engagement Ring for Galore!!! Rick Ross getting married

It pays to be Rick Ross' ride or die chick -- the Boss just iced up his GF Lira Mercer with an enormous diamond engagement ring that set him back $350,000.

Rick and Lira Galore have only been together for a few months. She was by his side during his Georgia arrest for kidnapping and assault, and the commitment has paid off.

We're told the centerpiece of the 11 carat sparkler is a whopping 5ct emerald-cut diamond. Ross didn't hold back on the wedding band either ... it's 6 carats and all diamonds.

Ross slipped the ring on Lira's finger in NYC, in the Rafaello & Company jewelry store. We're told he did NOT get on one knee.

The newly engaged couple celebrated with a chicken satay dinner at Red Sixes.