Can You Solve this Ice Diamond Riddle? ft. Vsauce’s Michael Stevens

If you think of it this way... as a diamond attached to the bottom of some ice, you can see that the water level will drop. The volume of water displaced by the diamond remains constant, but the volume of water displaced by the ice will be greater than normal because of the excess mass of the diamond pulling down the ice (creating an apparent higher density). Initially the water level would remain the same... until the volume ice could no longer offset the excess mass of the diamond. At the point of submergence the melting ice would lose volume as water and therefore lower the water level.  Wow I don't think that made it any clearer.