Derek Carr's days as a Raider may be numbered, but the guy was certainly a great teammate in Vegas ... 'cause the quarterback had custom diamond pendants made for Davante Adams and Maxx Crosby!!
TMZ Sports has learned, 31-year-old Carr wanted to show his appreciation for his guys ... so he asked Al The Jeweler from Labelle Jewelry in Totowa, NJ to come up with something extra special.
Al whipped together a pair of awesome pieces for Adams and Crosby -- black and white diamond pendants featuring their respective jersey numbers.
Of course, Carr and Adams go way back to their days at Fresno State ... and their friendship has continued throughout their pro careers.
Carr and Crosby have been teammates for four seasons ... and the two captains formed a tight bond during their time with the Raiders.
As we previously reported, Carr penned a goodbye message to Raider Nation earlier Thursday ... seemingly bringing his 9 years in Silver and Black to an end.
They might not be teammates moving forward, but as they say ... diamonds are forever!!