GUCCI MANE PROPOSES ON NBA KISS CAM ... Look At That ROCK!!!

Gucci Mane dominated the NBA Kiss Cam Tuesday night at the Atlanta Hawks game -- proposing to his GF with a diamond the size of a fist ... and the crowd went wild!!! 

The lucky lady is Keyshia Ka'oir -- who first met Gucci on the set of one of his music videos in 2010. 

The couple was sitting courtside when the kiss cam began to roll -- and though Gucci never got down on his knee, Keyshia didn't seem to mind once she saw that rock!! 

As for the Hawks, they lost 112-94 to the Pelicans ... but the mascot didn't care -- he was going crazy over the action in the stands! 

Congrats!