The mineral here labeled jeffersonite is probably aegirine. Labeled pegmatite, but is not igneous pegmatite. “Jeffersonite,” a term no longer used (except locally among collectors), variously refers to augite, diopside, and aegirine. X-ray and chemical methods are commonly needed for species certainty except by comparison to well-documented assemblages, but the preponderance of dark-brown clinopyroxene at Franklin is aegirine. Medium-brown specimens are often augite, and white to pale brown ones are generally diopside.