A combination thrust-bearing and radial bearing apparatus (500, 500'), comprising: a thrust-bearing assembly (502a, 502b) including: a thrust-bearing stator including a thrust-bearing stator support ring and at least one superhard stator thrust-bearing element mounted to the thrust-bearing stator support ring, the at least one superhard stator thrust-bearing element including a superhard thrust stator bearing surface, the at least one superhard stator thrust-bearing element positioned about an axis; and a thrust-bearing rotor including a thrust rotor support ring and at least one superhard rotor thrust-bearing element mounted to the thrust rotor support ring, the at least one superhard rotor thrust-bearing element including a superhard thrust rotor bearing surface generally opposed to the superhard thrust stator bearing surface; and a radial bearing assembly including: a radial bearing stator including a radial stator support ring and at least one superhard stator radial bearing element mounted to the radial stator support ring, the at least one superhard stator radial bearing element including superhard radial stator bearing surface, the at least one superhard stator radial bearing element positioned about the axis; and a radial bearing rotor including a radial rotor support ring and at least one superhard rotor radial bearing element mounted to the radial rotor support ring, the at least one superhard rotor radial bearing element including superhard radial rotor bearing surface generally opposed to the superhard radial stator bearing surface, and wherein at least one of the superhard stator thrust-bearing surface or the rotor thrust-bearing surface includes polycrystalline diamond, and at least one of the superhard stator radial bearing surface or the rotor radial bearing surface includes a non-diamond superhard material; and characterised in that the at least one superhard stator radial bearing element is positioned closer to the axis than the at least one superhard stator thrust-bearing element; and the at least one superhard rotor radial bearing element is positioned closer to the axis than the at least one superhard rotor thrust-bearing element. a thrust-bearing assembly (502a, 502b) including: a thrust-bearing stator including a thrust-bearing stator support ring and at least one superhard stator thrust-bearing element mounted to the thrust-bearing stator support ring, the at least one superhard stator thrust-bearing element including a superhard thrust stator bearing surface, the at least one superhard stator thrust-bearing element positioned about an axis; and a thrust-bearing rotor including a thrust rotor support ring and at least one superhard rotor thrust-bearing element mounted to the thrust rotor support ring, the at least one superhard rotor thrust-bearing element including a superhard thrust rotor bearing surface generally opposed to the superhard thrust stator bearing surface; and a thrust-bearing stator including a thrust-bearing stator support ring and at least one superhard stator thrust-bearing element mounted to the thrust-bearing stator support ring, the at least one superhard stator thrust-bearing element including a superhard thrust stator bearing surface, the at least one superhard stator thrust-bearing element positioned about an axis; and a thrust-bearing rotor including a thrust rotor support ring and at least one superhard rotor thrust-bearing element mounted to the thrust rotor support ring, the at least one superhard rotor thrust-bearing element including a superhard thrust rotor bearing surface generally opposed to the superhard thrust stator bearing surface; and a radial bearing assembly including: a radial bearing stator including a radial stator support ring and at least one superhard stator radial bearing element mounted to the radial stator support ring, the at least one superhard stator radial bearing element including superhard radial stator bearing surface, the at least one superhard stator radial bearing element positioned about the axis; and a radial bearing rotor including a radial rotor support ring and at least one superhard rotor radial bearing element mounted to the radial rotor support ring, the at least one superhard rotor radial bearing element including superhard radial rotor bearing surface generally opposed to the superhard radial stator bearing surface, and a radial bearing stator including a radial stator support ring and at least one superhard stator radial bearing element mounted to the radial stator support ring, the at least one superhard stator radial bearing element including superhard radial stator bearing surface, the at least one superhard stator radial bearing element positioned about the axis; and a radial bearing rotor including a radial rotor support ring and at least one superhard rotor radial bearing element mounted to the radial rotor support ring, the at least one superhard rotor radial bearing element including superhard radial rotor bearing surface generally opposed to the superhard radial stator bearing surface, and wherein at least one of the superhard stator thrust-bearing surface or the rotor thrust-bearing surface includes polycrystalline diamond, and at least one of the superhard stator radial bearing surface or the rotor radial bearing surface includes a non-diamond superhard material; and characterised in that the at least one superhard stator radial bearing element is positioned closer to the axis than the at least one superhard stator thrust-bearing element; and the at least one superhard rotor radial bearing element is positioned closer to the axis than the at least one superhard rotor thrust-bearing element.