QUARTZ AND FELDSPAR. - USGS
many open pits, from which feldspar, quartz, mica, or gem minerals have been mined, and in the cliffs along the seacoast, especially in the Boothbay Harbor region. ... intergrowth or interpenetration of single crystals of quartz and feldspar, the quartz forming, on certain faces of the feldspar crystals,