Isaiah Crowell ain't about to forget his first season with the Jets anytime soon ... 'cause the RB got a custom diamond pendant made to remember it forever!!!
TMZ Sports has learned the Jets star hit up Luxe Jewelers in Atlanta to make him some sick ice that commemorated his first year in NY ... and seems they delivered.
The drip -- which features Isaiah's No. 20 jersey and "Crow" nickname -- cost roughly $50,000 and has 12ct diamonds AND 150 grams of solid gold.
We're told the piece -- made by Ali G -- has diamonds that are all VS clarity .