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Hollofield Gabbro Quarries, Hollofield, Baltimore County, Maryland, USAi
Regional Level Types
Hollofield Gabbro QuarriesGroup of Quarries (Overgrown)
HollofieldUnincorporated Area
Baltimore CountyCounty
MarylandState
USACountry

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Latitude & Longitude (WGS84):
39° 18' 37'' North , 76° 47' 32'' West
Latitude & Longitude (decimal):
39.31034,-76.79237
GRN:
N27W43
Type:
Group of Quarries (Overgrown) - last checked 2024
Köppen climate type:
Cfa : Humid subtropical climate
Nearest Settlements:
PlacePopulationDistance
Milford Mill29,042 (2011)4.6km
Ellicott City65,834 (2011)4.8km
Woodlawn37,879 (2011)5.7km
Randallstown32,430 (2011)6.3km
Catonsville41,567 (2011)6.7km
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
ClubLocationDistance
Central Maryland Rock and Mineral Collectors ExchangeElkridge, Maryland13km
Baltimore Mineral SocietyBaltimore, Maryland16km
Chesapeake Gem & Mineral SocietyBaltimore, Maryland16km
Gem Cutters Guild of Baltimore, Inc.Baltimore, Maryland16km
Gem, Lapidary, and Mineral Society of Montgomery County, MD., Inc.Rockville, Maryland40km
Mindat Locality ID:
301420
Long-form identifier:
mindat:1:2:301420:5
GUID (UUID V4):
0


Two major openings of "Trap Rock" (Gabbro and Metagabbro) on the upper slopes of the hill overlooking the Patapsco River on the east bank, a half mile south of Hollofield. Both are now within Patapsco Valley State Park. Coordinates are situated between the two major pits. These deposits were last actively worked by E.E. Fagan circa 1909.

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.

Detailed Mineral List:

ⓘ 'Amphibole Supergroup'
Formula: AB2C5(T8O22)W2
References:
Stuart Herring CollectionIdentified by Stuart Herring: Visual Identification
ⓘ Aragonite
Formula: CaCO3
ⓘ Calcite
Formula: CaCO3
ⓘ 'Chlorite Group'
ⓘ Enstatite
Formula: Mg2Si2O6
ⓘ Enstatite var. Bronzite
Formula: (Mg,Fe2+)2[SiO3]2
ⓘ 'Garnet Group'
Formula: X3Z2(SiO4)3
ⓘ Laumontite
Formula: CaAl2Si4O12 · 4H2O
ⓘ Microcline
Formula: K(AlSi3O8)
References:
Stuart Herring
ⓘ Muscovite
Formula: KAl2(AlSi3O10)(OH)2
References:
Stuart Herring
ⓘ Pyrite
Formula: FeS2
ⓘ Pyrrhotite
Formula: Fe1-xS
ⓘ Quartz
Formula: SiO2
ⓘ Vermiculite
Formula: Mg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
ⓘPyrrhotite2.CC.10Fe1-xS
ⓘPyrite2.EB.05aFeS2
Group 4 - Oxides and Hydroxides
ⓘQuartz4.DA.05SiO2
Group 5 - Nitrates and Carbonates
ⓘCalcite5.AB.05CaCO3
ⓘAragonite5.AB.15CaCO3
Group 9 - Silicates
ⓘEnstatite9.DA.05Mg2Si2O6
ⓘvar. Bronzite9.DA.05(Mg,Fe2+)2[SiO3]2
ⓘMuscovite9.EC.15KAl2(AlSi3O10)(OH)2
ⓘVermiculite9.EC.50Mg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
ⓘMicrocline9.FA.30K(AlSi3O8)
ⓘLaumontite9.GB.10CaAl2Si4O12 · 4H2O
Unclassified
ⓘ'Amphibole Supergroup'-AB2C5(T8O22)W2
ⓘ'Chlorite Group'-
ⓘ'Garnet Group'-X3Z2(SiO4)3

List of minerals for each chemical element

HHydrogen
Hⓘ LaumontiteCaAl2Si4O12 · 4H2O
Hⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Hⓘ VermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
CCarbon
Cⓘ AragoniteCaCO3
Cⓘ CalciteCaCO3
OOxygen
Oⓘ Amphibole SupergroupAB2C5(T8O22)W2
Oⓘ AragoniteCaCO3
Oⓘ CalciteCaCO3
Oⓘ EnstatiteMg2Si2O6
Oⓘ LaumontiteCaAl2Si4O12 · 4H2O
Oⓘ MicroclineK(AlSi3O8)
Oⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Oⓘ QuartzSiO2
Oⓘ VermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
Oⓘ Enstatite var. Bronzite(Mg,Fe2+)2[SiO3]2
Oⓘ Garnet GroupX3Z2(SiO4)3
MgMagnesium
Mgⓘ EnstatiteMg2Si2O6
Mgⓘ VermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
Mgⓘ Enstatite var. Bronzite(Mg,Fe2+)2[SiO3]2
AlAluminium
Alⓘ LaumontiteCaAl2Si4O12 · 4H2O
Alⓘ MicroclineK(AlSi3O8)
Alⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Alⓘ VermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
SiSilicon
Siⓘ EnstatiteMg2Si2O6
Siⓘ LaumontiteCaAl2Si4O12 · 4H2O
Siⓘ MicroclineK(AlSi3O8)
Siⓘ MuscoviteKAl2(AlSi3O10)(OH)2
Siⓘ QuartzSiO2
Siⓘ VermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
Siⓘ Enstatite var. Bronzite(Mg,Fe2+)2[SiO3]2
Siⓘ Garnet GroupX3Z2(SiO4)3
SSulfur
Sⓘ PyriteFeS2
Sⓘ PyrrhotiteFe1-xS
KPotassium
Kⓘ MicroclineK(AlSi3O8)
Kⓘ MuscoviteKAl2(AlSi3O10)(OH)2
CaCalcium
Caⓘ AragoniteCaCO3
Caⓘ CalciteCaCO3
Caⓘ LaumontiteCaAl2Si4O12 · 4H2O
FeIron
Feⓘ PyriteFeS2
Feⓘ PyrrhotiteFe1-xS
Feⓘ VermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4 · 8H2O
Feⓘ Enstatite var. Bronzite(Mg,Fe2+)2[SiO3]2

Localities in this Region

USA

Other Regions, Features and Areas containing this locality

North AmericaContinent
North America PlateTectonic Plate

This page contains all mineral locality references listed on mindat.org. 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 mindat.org 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.

References

Singewald, J.T. (1928) Notes on feldspar, quartz, chrome and manganese in Maryland. Maryland Geological Survey Vol.XII, part 2: 112.
Ostrander, Charles W., Price, Jr, Walter E. (1940) Minerals of Maryland. The Natural History Society of Maryland, Baltimore, Maryland, USA. 14pp.p.20
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