"This book represents a first-ever attempt to explain and illustrate how the volcanic material pumice can be processed using simple technologies suitable for developing countries. In Germany, the first wall-building brick made of pumice and a slow-hardening binder (milk of lime) dates back to the year 1845. That marked the starting point of a local pumice-based building industry in volcanic regions of the Eifel Mountains, where pumice deposits were abundant. As time passed, the material's market area expanded steadily. Today's pumice industry in the Rhineland operates large production facilities and has enough raw material reserves to last beyond the turn of the century at the present rate of production. Pumice, an extremely light, porous raw material of volcanic origin, can be found in many parts of the world, including various developing countries with areas of past or present volcanic activity. In some countries, volcanic ash (with a particle size of less than 2 mm), pumice (with particle sizes ranging from 2 to 64 mm) and consolidated ash (tuff) are traditionally used, on a local scale, as versatile building materials."
"Building with pumice" (pdf-version), Klaus Grasser & Gernot Minke, 1990. More links: 1 / 2. Thanks to Zeltia González Blanco.
