Abstract: A method for manufacturing a sapphire single-crystal, including melting alumina and/or sapphire in a crucible, and bringing the molten alumina and/or sapphire in contact with a monocrystalline sapphire seed to make the molten alumina and/or sapphire crystallise progressively according to a growth direction to form the sapphire single-crystal. The monocrystalline sapphire seed has a rhombohedral crystallographic structure defining three crystallographic axes [A], [C] and [M] perpendicular to each other and respectively perpendicular to the crystallographic planes. The monocrystalline sapphire seed is a plate delimited by two planar faces which extend parallel to and at a distance from each other, is obtained from an initial sapphire single-crystal which is cut so that one of the crystallographic axes of the monocrystalline sapphire plate forms with a normal to the planar faces of the monocrystalline sapphire plate an angle whose value is comprised between 5 and 85°.