Qalo Ring

I wanna get my husband a qalo ring. He's military and with his job he's not allowed to wear his tungsten ring at work. I want to surprise him with it for his birthday but I have no idea what color to get. His favorite color is purple but I definitely know that he wouldn't wanna be wearing a purple ring around his buddies. I also know he doesn't want plain black cause he's not a plain Jane kinda guy. Any ideas on what color? If you were gonna get your husband one, what color would you get?