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Sunstone Knoll, Deseret, Millard Co., Utah, USAi
Regional Level Types
Sunstone KnollDeposit
Millard Co.County

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Latitude & Longitude (WGS84):
39° 8' 56'' North , 112° 42' 59'' West
Latitude & Longitude (decimal):
Locality type:
Nearest Settlements:
Deseret353 (2011)16.3km
Hinckley695 (2017)20.0km
Delta3,482 (2017)25.6km
Sutherland165 (2011)27.6km
Holden373 (2017)38.8km
Other/historical names associated with this locality:
Labradorite deposit

The Utah Geologic Survey states that
Sunstone Knoll is formed of volcanic vents that erupted during the early Pleistocene (1.6 million years to about 750,000 years ago). These eruptions left deposits of basaltic lava and volcanic breccia (angular, broken rock fragments held together in a matrix of finer grained material). Sunstone is a transparent, yellowish labradorite (a plagioclase feldspar mineral) found as crystals in these volcanic rocks and on the flats surrounding the knoll.

A feldspar-gemstone occurrence located in the SE¼SW¼NE¼ Section 23, Township 19 South, Range 8 West, Salt Lake Meridian, 16.3 km (10.1 miles) south-southwest of Deseret, along highway 257, on Bureau of Land Management administered land (located claim). The USGS MRDS database stated accuracy for this locality is 100 meters.

Mineralization is a volcanic deposit of Pleistocene basalt with feldspar crystals. The ore body is a blanket in form with a thickness of 15.24 meters, width of 152.4 meters, length of 304.8 meters, depth-to-top of 0.0 meters, and a depth-to-bottom of 15.24 meters. Local rocks include Quaternary Lake Bonneville deposits.

Workings include surface and underground openings comprised of a small open shaft at 50 feet deep plus several bulldozer cuts. The overall length is 167.64 meters, overall width is 30.48 meters and the overall depth is 15.24 meters.

Regions containing this locality

North America PlateTectonic Plate

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Standard Detailed Strunz Dana Chemical Elements

Commodity List

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

Mineral List

1 valid mineral.

Rock Types Recorded

Note: this is a very new system on and data is currently VERY limited. Please bear with us while we work towards adding this information!

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Alphabetical List Tree Diagram

Detailed Mineral List:

Formula: Ca(Al2Si2O8)
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10087082.
Anorthite var: Labradorite
Formula: (Ca,Na)[Al(Al,Si)Si2O8]
Reference: USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10087082.

List of minerals arranged by Strunz 10th Edition classification

Group 9 - Silicates
var: Labradorite9.FA.35(Ca,Na)[Al(Al,Si)Si2O8]

List of minerals arranged by Dana 8th Edition classification

Unclassified Minerals, Mixtures, etc.
var: Labradorite-(Ca,Na)[Al(Al,Si)Si2O8]

List of minerals for each chemical element

O Anorthite (var: Labradorite)(Ca,Na)[Al(Al,Si)Si2O8]
O AnorthiteCa(Al2Si2O8)
Na Anorthite (var: Labradorite)(Ca,Na)[Al(Al,Si)Si2O8]
Al Anorthite (var: Labradorite)(Ca,Na)[Al(Al,Si)Si2O8]
Al AnorthiteCa(Al2Si2O8)
Si Anorthite (var: Labradorite)(Ca,Na)[Al(Al,Si)Si2O8]
Si AnorthiteCa(Al2Si2O8)
Ca Anorthite (var: Labradorite)(Ca,Na)[Al(Al,Si)Si2O8]
Ca AnorthiteCa(Al2Si2O8)

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

Quaternary - Miocene
0 - 23.03 Ma

ID: 3185380
Cenozoic sedimentary rocks

Age: Cenozoic (0 - 23.03 Ma)

Lithology: Sedimentary rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

0.0117 - 2.588 Ma

ID: 2966549
Lake Bonneville deposits

Age: Pleistocene (0.0117 - 2.588 Ma)

Comments: Original map source: Hintze, L.F., Willis, G.C., Laes, D.Y.M., Sprinkel, D.A., and Brown, K.D., 2000, Digital Geologic Map of Utah: Utah Geological Survey, Map 179DM, scale 1:500,000.

Lithology: Major:{clay}, Minor:{sand,gravel,marl}, Incidental:{volcanic}

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]

Late Pleistocene - Middle Pleistocene
0.0117 - 0.781 Ma

ID: 2323860
Basalt of Deseret, Pot Mountain, Sunstone Knoll, Smelter Knolls, and Pahvant Butte

Age: Pleistocene (0.0117 - 0.781 Ma)

Description: Basalt of Deseret, Pot Mountain, Sunstone Knoll, Smelter Knolls, and Pahvant Butte --Basalt flows of probable middle and late Pleistocene age; 0 to 1,000 feet (0-300 m) thick.

Reference: Hintze, L.F., F.D. Davis. Geologic map of the Delta 30′ x 60′ quadrangle and part of the Lynndyl 30′ x 60′ quadrangle, northeast Millard County and parts of Juab, Sanpete, and Sevier Counties, Utah. Map 184 Utah Geological Survey. [44]

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


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Everts, M.L. (1979), on-site investigation, Sunstone Knoll, Millard County, Utah Geological and Mineral Survey.
Utah Geological And Mineral Survey (1979) Econ files, crib 27-Sunstone Knoll-3.
U.S. Bureau of Mines (1995), Minerals Availability System/Mineral Industry Location System (MAS/MILS), file #0490270103.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10087082 & 10275922.
USGS MRDS ID #D004654.

USGS MRDS Record:10087082

External Links (Sunstone Knoll webpage by the Utah Geological Survey.) (Sunstone Knoll webpage on the Millard County, Utah website.) (Additional detailed site information on The Diggings website.)

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