Marble, e.g. (3)
(Other definitions for orb that I've seen before include "Sphere - eye" , "A poetic eye, bro" , "Item of royal regalia" , "Jewelled ornament" , "Spherical object or shape" .)
(Other definitions for stone that I've seen before include "Hard lump of mineral matter" , "Boulder" , "See 21" , "Little rock" , "See 1" .)