User blog comment:Takeshi kun21/What is your Name?: Guide to Naming Your RWBY OC/@comment-9451720-20151203055922/@comment-24385282-20160219015509

They all relate to stone, so it could be a block (BLOC) of stone. The definition of block even specifies that blocks are typically made of stone or rock (or wood). BLOC should probably be fine for a team name, especially when all of its members' names are references to minerals andstones.