SUPPORT US. If is important to you, click here to donate to our Fall 2019 fundraiser!
Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsBooks & Magazines
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
Mining CompaniesStatisticsUsersMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryMineral Photography

Cross Hill Quarry (Pantano Clay deposit; Mineral Lease No. 23880C), Pantano Wash, Rincon District, Rincon Mts, Pima Co., Arizona, USA

This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84): 32° 0' 42'' North , 110° 35' 8'' West
Latitude & Longitude (decimal): 32.01167,-110.58556
Other regions containing this locality:Sonoran Desert, North America

Ref.: Funnell, J.E. & Wolfe, E.J. (1964), Compendium on nonmetallic minerals of Arizona. Southwest Research Institute, San Antonio: 98.

Patterson, S.H. (1969) Clay, in: USGS & Arizona Bureau of Mines, and U.S. Bureau of Reclamation (1969), Mineral and Water Resources of Arizona, Arizona Bureau of Mines Bull. 180 (USGS Bull.871): 332.

Keith, Stanton B. (1974), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 189, Index of Mining Properties in Pima County, Arizona: 141 (Table 4).

U.S. Department of Mine Safety and Health Administration (1978) Metal-Nonmetal Mine file reference.

U.S. Department of Mine Safety and Health Administration (MSHA) (1978) Metal-Nonmetal Mine Information Supplement, revised by MILS 11-79.

Arizona Department of Mines & Mineral Resources (1989), Directory of Active Mines in Arizona, incorporating sand and gravel operations 1989-1990, Arizona Department of Mines & Mineral Resources Directory 36, 14 pp.

Peirce, H. Wesley (1990), Arizona Geological Survey Industrial Minerals card file.

Phillips, K.A., Beard, R.R., Niemuth, N.J., and Bain, D.R. (1991) Active Mines in Arizona – 1992: Arizona Department of Mines and Mineral Resources Directory 39, 20 pp.

Arizona Bureau of Mines file data.

MRDS database Dep. ID file #10060262, MRDS ID #TC10261; and, Dep. ID #10186406, MAS ID #0040190534.

A former surface clay mining area located in the W½ sec. 26, South-central T.16S., R.17E., near Pantano Wash in eastern Pima County, about 25 miles SE of Tucson, N of interstate 10 and 2 miles NW of the Pantano interchange, on land of unknown status. Owned and operated by the Clinton Campbell Contracting, Inc. (1991). Previously operated by the Stewart Block and Brick Co.; Arizona Portland Cement Co. (1978); and, the California Portland Cement.

Mineralization is clay from Tertiary lake beds. The deposit is 4,500 meetrs long and 70 meters thick. It is possessed of good plasticity, good colours, good strength, and fires within 100 degrees C range, has a short and abrupt vitrification range, and low calcium carbonate content. This clay is a high-alumina fire clay composed of mixed kaolinite-illite clay minerals. For most uses, it is used in its natural colours - largely light to dark reddish browns.

The material is slightly indurated dark gray to brown shale. The shale occurs in a basin about 3 miles long and 1 mile wide. The deposit is about 35 meters thick at Cross Hill, but could be as thick as 70 meters about 2.5 km to the north. The deposit crops out over an area of more than 6 square km.

Worings include three pits. This deposit supplied almost half of all the clay mined in Arizona in 1992.

Mineral List

2 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

Tortonian - Rupelian
7.246 - 33.9 Ma
Middle Miocene to Oligocene sedimentary rocks

Age: Cenozoic (7.246 - 33.9 Ma)

Description: Con-glomerate, sandstone, mudstone, limestone, and rock-avalanche breccia (sheet-like deposits of crushed rock) deposited and tilted during widespread normal faulting and basin development. Sediments, mostly conglomerate and sandstone, are commonly medium to dark brown, reddish brown, or brownish gray; younger strata are generally lighter colors. Most deposits are 20 to 30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona. (11-32 Ma)

Comments: Middle Tertiary syntectonic or synextensional sucpracrustal rocks

Lithology: Major:{conglomerate,sandstone}, Minor:{mudstone,sedimentary breccia,limestone}

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.
Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © and the Hudson Institute of Mineralogy 1993-2019, except where stated. Most political location boundaries are © OpenStreetMap contributors. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: October 22, 2019 20:57:22 Page generated: October 13, 2017 18:32:51
Go to top of page