Blue cryptocrystalline tourmaline is the principal mineral in massive, pale-blue fault gouge2 3.5 miles north of Barstow, California. T. W. Dibblee, Jr., of the U. S. Geological Survey, collected samples from the north side of a low ridge in the SE 14 sec. 18, T. 10 N., R. 1 W., San Bernardino base and meridian (lat. 34° 57′ N., long. 117° 00′ W.). According to Dibblee (personal communication) the blue tourmaline rock, a lenticular mass roughly 30 feet long and 10 feet wide, occurs in a local shear zone in fine-textured, poorly bedded, greenish-brown lime-silicate rock within a thick series of dark-gray biotite-hornblende-feldspar schists.3

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