Crystal-Filled Cavities in Granitic Pegmatites BUR STING THE BUBBLE

摘要

In November 1991, Louis B. Spaulding Jr. (deceased 2013) invited me to his Little Three pegmatite mine near Ramona, California, to view the last of a string of crystal-filled miarolitic cavities that he had been mining from the main pegmatite dike on the property (see London et al. 2012 for additional details of the mine). Spaulding had been mining northward up a steeply dipping portion of his pegmatite, and the last of the pockets was beneath an oak tree whose roots encircled crystals of smoky quartz and le-pidolite (fig. 8-15 of London 2008). The pocket wall was friable to the east (90 degrees off the trend that Spaulding had been following), so I started digging in that direction with a screwdriver.