Formula: AlO(OH) Orthorhombic
Diaspore occurs as platy masses in highly aluminous metamorphic rocks associated with corundum. It is a common component of emery. Diaspore also is a common component of bauxite, aluminous soils and clays.
BARRON COUNTY: Dott and Dalziel (1972) report diaspore as a component of pipestone in the Blue Hills area where it is intergrown with kaolin, illite and quartz.
SAUK COUNTY: diaspore is a component of the metasaprolite and in veins at the base of the Baraboo Quartzite. Here is occurs with pyrophyllite, kaolin and muscovite. (Medaris and Dott, 2001).