The Spiders (24-7, 13-3 Atlantic 10) won their fourth straight game and have already clinched a first-round bye heading into next week's conference tournament. Cedrick Lindsay pitched in with 11 points.
Richmond went into halftime with a 37-30 lead, then dominated the second half, leading by as many as 17 points. Lindsay gave the Spiders their largest margin when he made a free throw after being fouled on a steal.
The Dukes (18-11, 10-6), who have lost four of their last five games, never got closer than 12 points the rest of the way.
Florida guard Brandone Francis-Ramirez has decided to leave the team after two seasons.
Oklahoma basketball coach Lon Kruger has hired Carlin Hartman as an assistant.
Authorities say former Michigan State basketball player Keith Appling has been charged with carrying a concealed weapon and other crimes.