Pegmatite Minerals of New YorkPegmatites are bodies of unusually coarse-grained rock formed deep in the crust of the Earth. They precipitated from a fluid phase separated from the residual granitic melt in the final stages of the solidification of magma. Generally, pegmatites have a granitic composition and occur as dikes, lenses or veins. Most of their minerals are more than 1 cm in diameter, but individual crystals can reach tens of meters in length. Simple pegmatites contain albite, quartz, microcline and possible minor muscovite. Complex pegmatites carry rare minerals such as columbite, beryl, zircon, monazite, polycrase and uraninite. The major pegmatites of New York occur primarily in Westchester, Saratoga, Warren and Essex Counties. They were an important industrial source of feldspar for ceramics and mica for insulators and also provided rare elements such as niobium, beryllium, and uranium for high tech industries.