Abstract: A multifaceted mirror 10 is formed of individual plane mirrors 15 bonded to a support element or core 11 by a cement 14 in positions that are accurately located independently of the core. A base 30 has faces 31 accurately in the plane of the mirror faces, and locator blocks 40 having plane reference surfaces are secured to faces 31 to provide supports for accurately locating mirrors 15. The core 11 is placed inside a positioned array of mirrors 15, and the gaps between the mirrors and the core are filled with a cement such as epoxy. Trim strips 20 can be added to extend between and over the edges of the mirrors.