Vote for your favorite mineral in #MinCup26! - Quartz vs. Asagiite
It's a classic vs a newbie as the most common named mineral in the crust Quartz is up against an exceedingly-rare sea foam-green mineral discovered just a few years ago Asagiite.
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Portsmouth Mine, Cuyuna North Range, Crow Wing County, Minnesota, USAi
Regional Level Types
Portsmouth MineMine (Flooded)
Cuyuna North RangeMountain Range
Crow Wing CountyCounty
MinnesotaState
USACountry

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Latitude & Longitude (WGS84):
46° 29' 22'' North , 93° 57' 59'' West
Latitude & Longitude (decimal):
Type:
Mine (Flooded) - last checked 2023
Nearest Settlements:
PlacePopulationDistance
Crosby2,345 (2017)1.1km
Ironton561 (2017)1.6km
Trommald101 (2017)4.3km
Cuyuna346 (2017)4.5km
Deerwood520 (2017)5.5km
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
ClubLocationDistance
Cuyuna Rock, Gem and Mineral SocietyBrainerd, Minnesota23km
Mindat Locality ID:
52898
Long-form identifier:
mindat:1:2:52898:9
GUID (UUID V4):
0
Other/historical names associated with this locality:
Portsmouth Extension


The Portsmouth mine is one of the largest open pits in the district; the pit has been formed by the combination of several smaller pits and underground mines: Portsmouth, SE1/4SE1/4 sec. 2; Wearne, SW1/4SE1/4 sec. 2; Osberg, SE1/4SW1/4 sec. 2; Chisholm-Williams, NW1/4NW1/4 sec. 11; Evergreen, NE1/4NW1/4 sec. 11; Healy, formerly part of Thompson, NW1/4NE1/4 sec. 11; and Meacham, NE1/4NE1/4 sec. 11. Development of the Portsmouth ore body began with the northward crosscutting from the Thompson underground mine into the northern part of the NW1/4NE1/4 sec. 11 in 1912 or 1913. The Wearne mine, SW1/4SE1/4 sec. 2, was stripped as an open pit in 1916. From the Portsmouth mine 13,127,832 tons were shipped through 1955, exclusive of ore mined from the Thompson mine.
The pit, eventually over 1,200 feet wide and nearly 2 miles long, exposed a thick and multiple repeated section of complexly folded Proterozoic Trommald Banded Iron Formation. Both oxidized and unoxidized ore occurred. Also exposed was a titaniferous argillite body of enigmatic origin. The deep mine pit was a popular launch site for high altitude balloon flights in the 1950's. The flooded pit and overgrown dumps of the mine site are now a major part of the Cuyuna Country State Recreation area. It is administered by the Minnesota Department of Natural Resources, and no collecting is permitted.

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.


Mineral List

Mineral list contains entries from the region specified including sub-localities

10 valid minerals.

Rock Types Recorded


Rock list contains entries from the region specified including sub-localities

Select Rock List Type

Alphabetical List Tree Diagram

Detailed Mineral List:

Aragonite
Formula: CaCO3
'Chlorite Group'
Goethite
Formula: Fe3+O(OH)
Grunerite
Formula: ◻Fe2+2Fe2+5(Si8O22)(OH)2
Hematite
Formula: Fe2O3
Kutnohorite
Formula: CaMn2+(CO3)2
Magnetite
Formula: Fe2+Fe3+2O4
Pyrite
Formula: FeS2
Quartz
Formula: SiO2
Siderite
Formula: FeCO3
Stilpnomelane
Formula: K4Fe2+48[Si64Al8]O164(OH)52 · nH2O
'Tourmaline'
Formula: AD3G6(T6O18)(BO3)3X3Z

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
Pyrite2.EB.05aFeS2
Group 4 - Oxides and Hydroxides
Magnetite4.BB.05Fe2+Fe3+2O4
Hematite4.CB.05Fe2O3
Quartz4.DA.05SiO2
Goethite4.FD.10Fe3+O(OH)
Group 5 - Nitrates and Carbonates
Siderite5.AB.05FeCO3
Kutnohorite5.AB.10CaMn2+(CO3)2
Aragonite5.AB.15CaCO3
Group 9 - Silicates
Grunerite9.DE.05◻Fe2+2Fe2+5(Si8O22)(OH)2
Stilpnomelane9.EG.40K4Fe2+48[Si64Al8]O164(OH)52 · nH2O
Unclassified
'Chlorite Group'-
'Tourmaline'-AD3G6(T6O18)(BO3)3X3Z

List of minerals for each chemical element

HHydrogen
H GoethiteFe3+O(OH)
H Grunerite◻Fe22+Fe52+(Si8O22)(OH)2
H StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
BBoron
B TourmalineAD3G6(T6O18)(BO3)3X3Z
CCarbon
C AragoniteCaCO3
C KutnohoriteCaMn2+(CO3)2
C SideriteFeCO3
OOxygen
O AragoniteCaCO3
O GoethiteFe3+O(OH)
O Grunerite◻Fe22+Fe52+(Si8O22)(OH)2
O HematiteFe2O3
O KutnohoriteCaMn2+(CO3)2
O MagnetiteFe2+Fe23+O4
O QuartzSiO2
O SideriteFeCO3
O StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
O TourmalineAD3G6(T6O18)(BO3)3X3Z
AlAluminium
Al StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
SiSilicon
Si Grunerite◻Fe22+Fe52+(Si8O22)(OH)2
Si QuartzSiO2
Si StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
SSulfur
S PyriteFeS2
KPotassium
K StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
CaCalcium
Ca AragoniteCaCO3
Ca KutnohoriteCaMn2+(CO3)2
MnManganese
Mn KutnohoriteCaMn2+(CO3)2
FeIron
Fe GoethiteFe3+O(OH)
Fe Grunerite◻Fe22+Fe52+(Si8O22)(OH)2
Fe HematiteFe2O3
Fe MagnetiteFe2+Fe23+O4
Fe PyriteFeS2
Fe SideriteFeCO3
Fe StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O

Other Databases

Wikipedia:https://en.wikipedia.org/wiki/Portsmouth_Mine_Pit_Lake
Wikidata ID:Q7232478
Link to USGS MRDS:10121901

Localities in this Region

Other Regions, Features and Areas containing this locality

North AmericaContinent
North America PlateTectonic Plate

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