Antonio Brown is gunning for G.O.A.T. status -- and he's starting with a sick new diamond ring!
Check out AB's new jewelry ... 6.5 carats, 1,000 diamonds and some serious meaning behind it.
Here's what we know ... the Steelers WR hit up Gabriel the Jeweler -- who works with superstars like Odell Beckham and Jarvis Landry -- and said he wanted a custom piece to symbolize his quest to become the greatest receiver to ever play.
Gabriel tells TMZ Sports .