Donate now to keep alive!Help|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on Mindat
What is a mineral?The most common minerals on earthMineral PhotographyThe Elements and their MineralsGeological TimeMineral Evolution
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Black Pearl Mine (Black Pearl group of claims; Camp Wood Tungsten Mine), Loco Gulch, Eureka District, Yavapai Co., Arizona, USA

This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84): 34° 41' 14'' North , 113° 2' 4'' West
Latitude & Longitude (decimal): 34.68722,-113.03444
Köppen climate type:BSk : Cold semi-arid (steppe) climate

A former underground W-Bi-Au-Ag-Mo-Cu-Be-Fluorspar-Quartz mine on 11 patented and 5 unpatented claims in secs. 7, 8 & 18, T.15N., R.7W. & secs. 12 & 13, T.15N., R.8W., approximately 600 feet East of Boulder Creek on the South side of Loco Gulch, 15 miles SW of Camp Wood. Discovered in 1914 by Mr. Wm. Conners, then owned by John Lawler & Homer R. Wood. Produced 1915-1935 & 1951-1956.

Mineralization is a vein deposit with tabular ore bodies en echelon. Dark gray hornblende granite is invaded by pegmatites and crops out beneath Tertiary lava flows. Ore control was faulting. Alteration was oxidation to at least 40 feet below the outcrop.

The principal vein strikes S.74ºE. and dips steeply SW. It is a quartz body 6,000 feet long, 3 feet wide, and 250 feet deep, in granite. Average width of the vein exposed is 4.2 feet. The wall rock is intensely altered to sericite. Gangue is coarsely crystalline grayish-white quartz.

Workings include stopes opened from short adits and shallow shafts with maximum depth of 70 feet below the outcrop. Longest adit is 1,565 feet (Veta adit), with 5 raises to surface, a 155 foot shaft with 700 feet of drifting and 3 stopes. Production was 62,100 pounds of average 70.0% WO3 (1915-1935).

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

15 valid minerals.

Regional Geology

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

1400 - 1600 Ma

ID: 2729043
Middle Proterozoic granitic rocks

Age: Calymmian (1400 - 1600 Ma)

Stratigraphic Name: Oracle Granite; Ruin Granite

Description: Mostly porphyritic biotite granite with large microcline phenocrysts, with local fine-grained border phases and aplite. Associated pegmatite and quartz veins are rare. This unit forms large plutons, including the Oracle Granite, Ruin Granite, granite in the Pinnacle Peak - Carefree area northeast of Phoenix, and several bodies west of Prescott. (1400-1450 Ma)

Comments: ~ 1.4 Ga

Lithology: Major:{granite}, Minor:{aplite}, Incidental:{pegmatite}

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. [133]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Wilson, E.D. (1941), Tungsten Deposits of Arizona. Arizona Bureau of Mines Bull. 148: 21-22.
Anderson, C.A. (1955) Geology and Ore Deposits of the Bagdad Area, Yavapai County, Arizona. USGS PP 278.
Brownell, G.M. (1959), A beryllium detector for field exploration, Econ.Geol.: 54: 1103-1114;
Galbraith, F.W. & D.J. Brennan (1959), Minerals of Arizona: 80.
Dale, V.B. (1961), Tungsten deposits of Gila, Yavapai, and Mohave Counties, Arizona, U.S. Bureau of Mines Information Circular 8078: 43.
Lemmon, D.M., and Tweto, O.L. (1962) Tungsten in the U.S., USGS map, MR-25.
Staatz, M.H., et al (1965), Differences in the minor element composition of beryl in various environments, American Mineralogist: 50: 1783.
Meeves, H., et al (1966), Reconnaissance of beryllium-bearing pegmatite deposits in six western states, U.S. Bureau of Mines Information Circular 8298: 21 (Table A-1).
Phillips, K.A. (1987), Arizona Industrial Minerals, 2nd. Edition, Arizona Department of Mines & Minerals Mineral Report 4, 185 pp.
Schmitz, Christopher, and DONALD M BURT. "The Black Pearl mine, Arizona- Wolframite veins and stockscheider pegmatite related to an albitic stock." Global catastrophes in Earth history. Boulder, CO, Geological Society of America(Geological Society Special Publication, 247 (1990): 221-232.
Sawyer, M.B., Gurmendi, A.C., Daley, M.R., and Howell, S.B. (1992) Principal Deposits of Strategic and Critical Minerals in Arizona, U.S. Bureau of Mines Special Publication, 334 pp.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 134, 139, 424.
Flagg, A.L., Vanadium Report, Book VI (unpublished).
Lemmon, D.M., unpublished data.
USGS Bagdad Quadrangle map.
Arizona Department of Mineral Resources Black Pearl file.
MRDS database Dep. ID #10027556, MRDS ID #M003351; and, Dep. ID #10161782, MAS ID #0040250233.

Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2018, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: January 22, 2018 06:40:02 Page generated: January 4, 2018 03:00:45
Go to top of page