Forget plaques and record books ... Derrick Henry has found a new way to show off his legendary football resume -- an insane iced-out diamond chain!!
TMZ Sports has learned ... the Tennessee Titans star RB wanted to turn all of his pigskin accomplishments -- starting from high school -- into some bling for his 28th birthday this week.
So, he hit up celebrity jeweler Ali The Ice Champ in Dallas ... and the dude delivered the amazing piece in time for Henry's cake day this week.