Table facet This is the largest facet of a diamond. It is located on the top of the diamond. The table facet is sometimes referred to as the "face."

Table spread Term used to describe the width of the table facet, often expressed as a percentage of the total width of the stone.

Tension setting A tension-set diamond is held in place by the pressure of the band's metal, which is designed to "squeeze" the stone.

Tolkowsky, Marcel In 1919 Marcel Tolkowsky calculated the best theoretical compromise for the cut of a diamond to release the most beauty. The width of the table facet was found to be 53% of the total width of the stone, with a pavilion angle of 40 degrees and 45 degrees. The Tolkowsky cut provides the basis for the modern American cut.

Trillion Shape This is a triangular-shaped diamond with 50 facets. Trillions are commonly used as side stones