Classic Tension Setting
The tension setting, as its names suggests, secures the diamond in the ring through the pressure exerted by the metal band on either side of the stone. The diamond, therefore, appears to be suspended, or floating, between the two sides of the band. It is the ring itself which holds the diamond, as opposed to any claws, bezel or lip.
When designing this type of ring it is essential to have exact dimensions of the stone to ensure a perfect fit of the central stone. To add support the jeweller expertly cuts tiny grooves into the sides of the band. This ensures that the diamond, or other precious stone, is held securely by the pressure of the custom-designed metal band.
Tension-style settings feature a comparable look of diamond suspension. The main advantage being that they are less expensive and complicated to make. In addition, they provide added security for the centre stone since they feature a prong or bezel setting on the side or underneath the diamond to anchor it firmly in place.
In the two photos below, the one on top (two-tone metal with pear shape diamond) is a classic tension setting, whilst the one underneath is a tension-style setting. Notice the bezel setting around the round diamond in the tension-style setting.