Forelesninger holdt ved Advanced Study Institute of Feldspar - Oslo 1962
Lectures held at Advanced Study Institute of Feldspar - Oslo 1962

Many of the altered phenocrysts of K-feldspar in the Lincoln Porphyry near Leadville, Colorado, show small but real extemal deviations from monoclinic geometry. All of the evidence indicates that distortion of normal monoclinic feldspar rather than initial triclinic crystallization is responsible.