Buff top describes a hybrid cut: the crown is left as a smooth, polished dome in the manner of a cabochon, while the pavilion beneath is faceted. The result marries the soft, unbroken surface of a cabochon with the light handling of a faceted stone, giving a gem that reads quietly from above yet retains life through the back.
This page gathers the buff top stones currently in our collection. At present the cut appears here on Blue Star Sapphire, and for good reason. Asterism — the six-rayed star produced by fine oriented needle inclusions within corundum — requires a curved, domed surface to gather and focus the reflected rays. A flat, fully faceted crown would scatter the effect entirely, so the domed top is not a stylistic choice but a technical requirement.
When choosing, weigh the sharpness and centring of the star, the height and symmetry of the dome, and how the body colour sits beneath it. Domes carry depth, so consider how the stone will seat in a setting and how it will meet the light it is worn in.