In the second half of the 19th century new methods for quarrying and processing natural stone are developed. In the Nordic countries Sweden, Norway and Finland this technological pro­gress goes hand in hand with a systematic geological mapping and large-scale exploitation of natural stone deposits. As a result, new constructions are developed—changing the building practice in these countries. With the end of historicism a new architecture arises that particularly in Norway and Finland acquires a national-romantic character. This paper examines the interaction between geological exploration, commercial development, technical inventions and the development of a national-romantic architecture.