Jacumba District, San Diego Co., California, USA

The Jacumba District is a gemstone producing area spanning approximately 10 miles around the town of Jacumba, encompassing the southern end of the Jacumba Mountains to the northeast, Carrizo Gorge, and the In-Ko-Pah Mountains to the northwest.

In 1914, Merrill reported that 8.5 miles northwest of Jacumba was the Crystal Gem mine, at which in a pegmatite dike, had been found pink and green beryl and essonite garnet.

Merrill also reported that 9.5 miles east of Jacumba, near Mountain Springs, were deposits of essonite garnet in crystalline limestone associated with gneiss. Some fine gems were said to have been mined and marketed by the San Diego Gem Company under the name of "California hyacinth". Merrill noted that these mining claims were considered abandoned by 1914.

References:
Fisher, J. 2002. Gem and rare-element pegmatites of southern California; Jacumba District. Mineralogical Record 33(5): p. 403-404.

Kunz, G. F. 1905. Gems, jeweler's materials, and ornamental stones of California. California State Mining Bureau bulletin 37: p. 152.

Merrill, F. J. H. 1914. Geology and Mineral Resources of San Diego and Imperial Counties: Gems, Lithia Minerals. California State Mining Bureau, San Francisco, Cal. California State Printing Office, December. Chapter 1, pages 61-110.

Mudoch, J. and Webb, R. W. 1948. Minerals of California, Bulletin 136. State of California, Department of Natural Resources, Division of Mines, p. 70.

Rynerson, F. J. 1967. Exploring and mining for Gems and Gold in the West. Happy Camp, California: Naturegraph Publishers, Inc.: pages 8, 20, 40, 48, 204pp.

Sinkankas, J. 1997. Gemstones of North America. Vol. 3. Beryl; Spodumene; Tucson, Arizona: Geoscience Press Inc.; pages 59-60, 433-434, 480pp.

Weber, F. H. 1963. Geology and mineral resources of San Diego County, California. California Division of Mines and Geology, County Report 3: pages 101, 152.