Cardi B's Birthday Diamond Ring Worth More Than $1 Million

Cardi B isn't kidding when she raps about liking diamonds, stunting, shining and million dollar deals -- enter Offset with her whopping 20-carat birthday gift, which IS worth over SEVEN FIGURES!!!

The Migos rapper reached out to Pristine Jewelers in NYC about 9 months ago -- and owner  Avi Davidov tells us Offset made it clear he was looking to score something incredibly special for Cardi's 27th birthday.

We're told Offset already had an idea in his mind -- a heart-shaped diamond surrounded by smaller hearts. The center stone is a brilliant 20 carats. The diamond ring's been dubbed the Titanic Diamond for its size and similarity to the Heart of the Ocean rock from the movie. It's complemented by a band of smaller diamonds that total 25 carats.

We're told Avi literally hand-delivered the rings on a silver platter last weekend. As we reported ... Cardi was damn near knocked off her heels when she saw the stunning rings.