Formula: NaCa2(HSi3O9) Triclinic
Description: Pectolite usually forms from hydrothermal fluids as a vein or amygdule filling in basaltic volcanic rocks. It may also form in silica poor syenites and marbles.
BAYFIELD COUNTY: Pectolite occurs as white fibers in amygdules in Keweenawan basalts exposed in roadcuts along state highway 27 in the NE SE sec. 32 T. 44N. R.9W. Here it is associated with prehnite, chlorite and quartz. (W. S. Cordua field notes).