Senior center Andrew Smith scored a game-high 15 points, while sophomore forward Roosevelt Jones added his second double-double of the season in teh victory.
The win was the 12th straight for the No. 13-ranked Bulldogs.
Butler (15-2, 3-0 A-10) played its first home A-10 game without Clarke, who was injured in the Bulldogs' victory at Dayton on Saturday. Clarke, who stands third in the A-10 in scoring with a 16.3 average, suffered a severe neck sprain and is sidelined indefinitely.
Without Clarke, the Bulldogs turned to Smith, the reigning A-10 Player of the Week, and Jones, and both players delivered. The 6-foot-11 Smith hit six of nine shots and added three free throws, seven rebounds and three assists. Jones chipped in with 10 points, a game-high 12 rebounds, four assists and three steals.
The Bulldogs also picked up 11 points from freshman Kellen Dunham, who took Clarke's spot in the starting lineup, and eight points and seven rebounds from sophomore Kameron Woods in a reserve role.
"I'm really proud of these guys," Butler coach Brad Stevens said in a release. "That was a great win. That's a hard team to play against. It's a hard team to prepare for. They're unique in many ways. I'm glad we scheduled Northwestern and Vanderbilt, because they run similar stuff."
Richmond (11-7, 1-2 A-10) scored the first basket of the game, and that wound up being the Spiders' lone lead in the contest. The game was tied twice in the early going, the last coming at 8-8. The Bulldogs scored the next seven points, three by Jones, a three-point field goal by junior Erik Fromm and a free throw by Smith, to grab the lead for good.
Sophomore Alex Barlow nailed a three-point field goal with five seconds remaining in the first half to give the Bulldogs their biggest first half margin, a 33-21 halftime lead.
That lead grew to as many as 20, 46-26, on a three-point field goal by sophomore Andrew Smeathers with 12:41 left in the game. The Spiders did make a late run and cut Butler's lead to nine, 50-41, but the Bulldogs finished with a 12-6 run in the final 8:23 for the 15-point win.
Fueling Butler's win was a commanding advantage in rebounds. The Bulldogs out-rebounded the conference foe, 53-20. Butler's 20 offensive rebounds led to a 21-6 advantage in second chance points.
"We needed that," Stevens said. "That was our advantage tonight. (Richmond's) guards can really go and score the ball, but they're small with (Derrick) Williams out. So that was going to be a major emphasis for us. We talked all week about getting on the glass."
Williams, a 6-6, 275-pound forward and the Spiders' leading rebounder, missed his fourth straight game with a sprained ankle.
Darien Brothers, the top three-point field goal shooter in the A-10, led Richmond with 12 points, but he only hit one of seven shots from beyond the three-point arc.
Butler will step out of conference play on Saturday and host No. 8 Gonzaga. The match-up of the two nationally-ranked teams will start at 9 p.m. and will be televised nationally on ESPN.