The mica-covered “Block” lamp continues the theme of Frank’s fascination for materials coupled with austerity of form. For this work the designer covered a simple rectangular block in a regular grid of mica sheets. Mica has a natural metallic luster and, just like the rock crystal lamps, lent captivating texture and sparkle to his interiors. Frank reserved the use of mica for some of his most important commissions, such as the sitting room of Charles and Marie-Laure de Noailles, where he clad the fireplace surround in mica. The same treatment appeared again in Templeton Crocker’s San Francisco penthouse. Mica-covered tables appeared in the designer’s own smoking room (1938).