The optical switching properties of switchable mirrors based on alloys of magnesium and alkaline-earth metals, such as Ca, Sr, and Ba, were studied systematically using a gasochromic method. All prepared switchable mirrors showed excellent switchable mirror properties, and high visible transmittance and color neutral appearance in their transparent states. The achromatic properties with high visible transmittance may be because the hydrides of these alloys show grayish neutral color appearance. (C) 2011 Elsevier B.V. All rights reserved.