Blue Hills Rhyolite, Milton, MA

50x ppol*, 50x xpol*, 50x ppol, 50x xpol

Lynn Rhyolite, Marblehead, MA

50x ppol, 50x xpol, 50x xpol, 100x xpol

Attleboro Red Felsite, Attleboro, MA

50x ppol, 50x ppol, 100x xpol

Mt. Kineo Rhyolite

50x ppol a, 50x ppol, 50x xpol a, 50x xpol, 100x ppol, 100x xpol

Jefferson Rhyolite, Jefferson, NH

50x ppol, Sphere, 50x xpol, Sphere, 50x xpol

Parrat "Jasper", Berkshire Co., MA

50x ppol, 50x xpol, 100x xpol

Conklin Quarry "Jasper", RI

50x ppol, 50x xpol

Normanskill Chert, Coxsackie, NY

50x xpol, 100x xpol

Onondaga Chert, New Scotland, NY

50x ppol, Chalcedony, 50x ppol, 50x xpol

*ppol = plane-polarized light, xpol = cross-polarized light