Opal Mountains Agate Field prospect (Black Mountain; Black Mtn), Opal Mountain, San Bernardino Co., California, USA
|Latitude & Longitude (WGS84):||35° 8' 53'' North , 117° 11' 50'' West|
|Latitude & Longitude (decimal):||35.14806,-117.19750|
|Köppen climate type:||BWk : Cold desert climate|
A semiprecious gemstone (agate) occurrence located in the center sec. 18, T32S, R45E, MDM, 1.6 km (1.0 mile) SW of Opal Mountain (coordinates of record), on Bureau of Land Management administered land. MRDS database stated accuracy for this location is 500 meters.
Local rocks include Quaternary volcanic flow rocks, unit 7 (Mojave Desert).
Workings include unspecified surface openings.
2 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Zanclean - Aquitanian|
3.6 - 23.03 Ma
|Tertiary pyroclastic and volcanic mudflow deposits, unit 8 (Northern Mojave Desert)|
Age: Neogene (3.6 - 23.03 Ma)
Stratigraphic Name: Gem Hill Formation (part); Kinnick Formation; Pickhandle Formation
Description: Tertiary pyroclastic and volcanic mudflow deposits.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
California Division of Mines and Geology Bulletin 188 (1968): 60-61, Pl. 1.
Ferguson, R. W. (1979), Some field trips are like that: Lapidary Journal: 33(4): 1012-1014, 1018.
U.S. Bureau of Mines (1995), Minerals Availability System/Mineral Industry Location System (MAS/MILS): file #0060710939.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10188856.