Apply a dab of Loctite gel to Swarovski Setting and place rivoli stone inside. Place on a level surface to dry (if you can find a flat Styrofoam remnant, press the setting in before gluing the crystal, to create a divot.)
Set square cushion stone in JBB setting using nylon jaw pliers to fold down one corner, then the opposite, and then the remaining two. This will help keep the stone straight.
Attach the set rivoli to the open loop of the cushion setting and close loop. (See Jewelry Basics 101). Attach earwire to closed loop on cushion setting. Add wire keeper for additional security.