The hearts and arrows effect is a prevalent, visual imaging present in round brilliant diamonds whose cut, polish and symmetry are all graded as excellence. When the diamond is viewed using a hearts and arrows scope, the visual appearance is a repeatable, near perfect pattern of eight symmetrical arrows in the face-up position of the stone (called 'crown') and eight symmetrical hearts when viewed in the table-down position (called 'pavilion'). Less than 1% of the world's diamonds are cut to hearts and arrows optical symmetry precision. GIA certificates will sometimes contain a comment stating "Laser Inscription: H&A." This note on the GIA certificate indicates that "H&A" was laser inscribed on the diamond to reflect a visual appearance of hearts and arrows.
The picture to the top right indicates the an hearts and arrows effect of a triple excellence cut diamond as viewed under a hearts and arrows scope.