An orifice (262, 362) for a high-pressure waterjet cutter, the orifice (262, 362) comprising: a first surface (274, 374); a second surface (282, 382); an inner bore including a frustoconical portion (298, 398); a first layer (310, 410) extending from the first surface (274, 374) to a plane (314, 414) between the inlet plane and the outlet plane; and a second, separate layer (334, 434) extending from the plane (314, 414) to the second surface (282, 382), wherein the orifice (262, 362) further comprises that, the first surface (274, 374) defines an inlet plane; the second surface (282, 382) defines an outlet plane; the inner bore is aligned along a flow axis and extending from the first surface (274, 374) to the second surface (282, 382), wherein the inner bore includes a cylindrical portion (294, 394) adjacent the inlet plane and the frustoconical portion (298, 398) extending from the cylindrical portion (294, 394) to the outlet plane, the frustoconical (298, 398) portion having a maximum diameter at the outlet plane; the first layer (310, 410) and second layers (334, 434) coupled to one another to define a single component; and characterised in that, the first layer (310, 410) and the second layer (334, 434) are polycrystalline diamond and the second layer (334, 434) has material properties different than the first layer (310, 410), wherein either: a) the first layer (310, 410) of polycrystalline diamond provides superior impact resistance when compared to the second layer (334, 434) of polycrystalline diamond; or b) the second layer (334, 434) of polycrystalline diamond provides superior cavitation resistance when compared to the first layer (310, 410) of polycrystalline diamond; or c) the second layer (334, 434) of polycrystalline diamond provides superior wear resistance when compared to the first layer (310, 410) of polycrystalline diamond; or d) the first layer (310, 410) provides superior impact resistance when compared to the second layer (334, 434), the second layer (334, 434) provides superior cavitation resistance when compared to the first layer (310, 410), and the second layer (334, 434) provides superior wear resistance when compared to the first layer (310, 410). a first surface (274, 374); a second surface (282, 382); an inner bore including a frustoconical portion (298, 398); a first layer (310, 410) extending from the first surface (274, 374) to a plane (314, 414) between the inlet plane and the outlet plane; and a second, separate layer (334, 434) extending from the plane (314, 414) to the second surface (282, 382), wherein the orifice (262, 362) further comprises that, the first surface (274, 374) defines an inlet plane; the second surface (282, 382) defines an outlet plane; the inner bore is aligned along a flow axis and extending from the first surface (274, 374) to the second surface (282, 382), wherein the inner bore includes a cylindrical portion (294, 394) adjacent the inlet plane and the frustoconical portion (298, 398) extending from the cylindrical portion (294, 394) to the outlet plane, the frustoconical (298, 398) portion having a maximum diameter at the outlet plane; the first layer (310, 410) and second layers (334, 434) coupled to one another to define a single component; and characterised in that, the first layer (310, 410) and the second layer (334, 434) are polycrystalline diamond and the second layer (334, 434) has material properties different than the first layer (310, 410), wherein either: a) the first layer (310, 410) of polycrystalline diamond provides superior impact resistance when compared to the second layer (334, 434) of polycrystalline diamond; or b) the second layer (334, 434) of polycrystalline diamond provides superior cavitation resistance when compared to the first layer (310, 410) of polycrystalline diamond; or c) the second layer (334, 434) of polycrystalline diamond provides superior wear resistance when compared to the first layer (310, 410) of polycrystalline diamond; or d) the first layer (310, 410) provides superior impact resistance when compared to the second layer (334, 434), the second layer (334, 434) provides superior cavitation resistance when compared to the first layer (310, 410), and the second layer (334, 434) provides superior wear resistance when compared to the first layer (310, 410). a) the first layer (310, 410) of polycrystalline diamond provides superior impact resistance when compared to the second layer (334, 434) of polycrystalline diamond; or b) the second layer (334, 434) of polycrystalline diamond provides superior cavitation resistance when compared to the first layer (310, 410) of polycrystalline diamond; or c) the second layer (334, 434) of polycrystalline diamond provides superior wear resistance when compared to the first layer (310, 410) of polycrystalline diamond; or d) the first layer (310, 410) provides superior impact resistance when compared to the second layer (334, 434), the second layer (334, 434) provides superior cavitation resistance when compared to the first layer (310, 410), and the second layer (334, 434) provides superior wear resistance when compared to the first layer (310, 410).