German Expressionist architectural design is generally noted for its free, frenetic forms, for design that left behind all conventions. The futuristic Expressionist glass projects in both amorphous and crystalline arrangements can be seen as an expression of the utopian expectations for a new society after the German Revolution of 1918. Expressionist manifestoes and literature, on the other hand, reveal a thoroughgoing interest in a literary-architectural convention associated with glass and crystal, an iconographic theme that stretches from King Solomon, Jewish and Arabic legends, medieval stories of the Holy Grail, through the mystical Rosicrucian and Symbolist tradition down to Expressionism. Expressionist architects, familiar with the various earlier conventions, in a highly eclectic fashion reinterpreted the meaning of the glass-crystal symbolism as a metaphor of transformation to signify a changed society. This article, though it begins and ends with a discussion of Expressionist design, deals primarily with the sources and changes of this iconographic tradition.