Feldspar Feldspar Feldspars (KAlSiO – NaAlSiO – CaAlSiO) are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight. Feldspars crystallize from magma as veins in both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar (see below) is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. The name "feldspar" derives from the German "Feldspat", a compound of the words "Feld", "field", and "Spat", "a rock that does not contain ore". The change from
Copia: Foundations of the Abundant Style on Quintillian's rhetorical guide, "Institutio Oratoria". The first chapter of book 10 in Quintillian's "Oratoria" is titled ""De copia verborum"". This is quite possibly where Erasmus received his most direct inspiration for the book. In that 10th chapter, Quintillian declined to give examples for employing the abundant style, on the grounds that each individual case requires a unique solution. This left the door open for Erasmus to detail the abundant style in "Copia". Erasmus acknowledges Quintillian in the preface, and borrows from him (and other classical authors) throughout "Copia", sometimes citing, sometimes not. As further revisions of "Copia" are printed,