Hearts & Arrows is a style of cutting for a round brilliant that results in an extremely precise level of optical symmetry.
The term used for any round brilliant diamond that exhibits a kaleidoscopic pattern of hearts in the pavilion and arrows in the crown due to the precise physical symmetry of its cut. These patterns may be seen and photographed using a reflecting and magnifying device called a Hearts & Arrows viewer.
H&A can be branded or unbranded. Some sellers carry a certain 'brand,' produced by one manufacturer, and other sellers select H&A for their inventory from different suppliers according to their standards.