Description: Pectolite Castle Danger, the Rock Yard, Minnesota, USA About 5 X 9 X 9 cm Radiating clusters of Pectolite crystals and another mineral, possibly xonotlite, in a dark green mix of augite and plagioclase altered to prehnite. About 5 X 9 X 9 cm, the specimen is an amygdule containing the pectolite, surrounded by prehnite. This was described in a 1924 article by G. M. Schwartz of the U of MN in the American Mineralogist, pp. 83 - 88.

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