A decorative mirrored tile or the like preferably comprises a square transparent plate of glass or the like of substantially the same thickness throughout including the marginal portions thereof, and a mirror-forming surface at the rear of the plate extending to the margins thereof. There is provided along a band at each margin of the plate innumerable, tiny, spaced light interrupting areas or spots contrasting to the light transmitting characteristics of the tile between the same and the density of which varies progressively in a direction generally parallel to the plate margin involved, reaching maximum and minimum densities respectively at opposite ends thereof where they terminate along respective lines substantially bisecting the angle between the plate edges intersecting the corners of the plate thereat. An appearance of a mitered edge is provided at each corner of the plate by placing the dense end of each of the bands of light interrupting areas or spots along one margin of the plate adjacent to the least dense end of the band of light interrupting areas or spots at the adjacent margin of the plate.