| [var. Chalcedony] (2005) Mineral Resources Data System (MRDS), US Geological Survey. Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 316. California Journal of Mines and Geology (1954): 50(1) January, 1954: 211 |