“…High water content in silicate melts delays nucleation and depresses the glass transition temperature hundreds of degrees, which allows significant degrees of undercooling, as shown by microthermometry studies, melt inclusion analyses, both major element and oxygen isotope partitioning among feldspars, and lack of tartan twinning in potassic feldspars (Staatz et al, 1963, Nabelek et al, 1992, Morgan and London, 1999, Webber et al, 1999, Thomas et al, 2000, and Thomas and Davidson, 2012. Thomas and Davidson (2012) suggest, based on melt inclusion analyses, that pegmatite melts can contain 10 to 50 wt.…”