a place expressly for camaraderie, merriment, good will and good cheers

a place of courtesy, good breeding, and good manners

a place to relax but also the operations needs to be controlled

a place where mediocrity is made to feel comfortable

a place where one need not feel stigmatized or face denigrating remarks, regarding his or her intellectual integrity

a special place where good AA meetings

Nowadays diamond clubs and bourses tend to be interchangeable. Originally, a diamond club was primarily a place to trade rough diamonds, and a bourse was for polished goods.