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SHONKINITE, IG-125. California. Medium to coarse grained dark brown mica, pink feldspar and pale green pyroxene. SYENITE, IG-130. California. Medium to coarse grained tan to reddish alkali feldspar with up to 5% mafics. NEPHELINE SYENITE, IG-130A. Canada. Medium to coarse grain nepheline with 5 - 1 0% pyroxene, biotite and minor plagioclase in 1- 5 mm grains. HORNBLENDE SYENITE, IG-130B. Canada. Very coarse grain, about 50% reddish to brown alkali feldspar. SYENITE PORPHYRY, IG-130D. Nevada. Spectacular. With euhedral orthoclase phenocrysts in aphanitic yellow- brown alkali feldspar groundmass. TONALITE, see under DIORITE WELDED TUFF - IGNIMBRITE, IG-140 A, Nevada. Fiamme obsidian through out a black and white groundmass of welded volcanic ash. Assorted accessory minerals visible include alkali feldspar and quartz.
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