Mineral Evolution Database
Created and maintained by the Mineral Evolution Project in partnership with RRUFF and mindat.
Mineral locality data provided by mindat.org



The Mineral Evolution database is currently under development.

The goal of this page is to present localities at which the mineral is found, and estimates of the oldest possible geologic age of the minerals at these localities.


Locality Name:
Maryland, USA

Oldest recorded age at locality: 1231.5
Youngest recorded age at locality: 444

mindat Locality ID: 14027
mindat URL: http://www.mindat.org/loc-14027.html

Tectonic Settings:

Total number of sublocalities beneath "Maryland, USA": 776
Total number of bottom-level sublocalities: 657

Number of Child Localities: 24
Child Localities:
Allegany Co.
Anne Arundel Co.
Baltimore City
Baltimore Co.
Calvert Co.
Caroline Co.
Carroll Co.
Cecil Co.
Charles Co.
Dorchester Co.
Frederick Co.
Garrett Co.
Harford Co.
Howard Co.
Kent Co.
Montgomery Co.
Prince Georges Co.
Queen Annes Co.
Somerset Co.
St. Mary's Co.
Talbot Co.
Washington Co.
Wicomico Co.
Worcester Co.

Latitude: 39°3'21"N
Longitude: 76°42'49"W
Decimal Degree (lat, lon): 39.055833333333,-76.713611111111
AThis mineral is Anthropogenic.
GThis mineral is directly dated.
BThis mineral is reported as having this age.
YThis mineral is using an age reported as an element mineralization period.
OThis mineral is using an age calculated from all data at the locality.
RThe age displayed for this mineral originates from a different, non-child locality.
PThe age displayed for this mineral is the range of ages for this mineral at all of this locality's children.
This mineral's age has not yet been recorded.

This Mineral list contains entries from this locality, including sub-localities. Minerals in bold are reported by mindat.org as occurring directly at this locality, and do not occur at any children (sublocalities) of this locality.

Elements at this locality, including sub-localities: Ag Al As Au B Ba Be Bi C Ca Co Cr Cu F Fe H K Mg Mn Mo Na Ni O P Pb S Sb Si Sr Te Ti U Zn Zr 

Elements from minerals reported directly at this locality: 

Structural Groups for minerals in this locality: 
AllophaneAluniteAmorphousAmphiboleAnalcimeApatiteAragoniteArsenopyriteAuricuprideAutunite
BaryteBerylBrochantiteBruciteCalciteChabaziteChalcanthiteChalcopyriteChloriteChloritoid
ClayClinozoisiteCopiapiteCopperCoronaditeCorundumCovelliteDiasporeEpidoteFeldspar
FluoriteGarnetGypsumHarmotomeHeulanditeHydrotalciteIronKaoliniteLipscombiteMalachite
MarcasiteMelanteriteMicaMilleriteMolybdeniteNatroliteNickelineNoneNot in a structural groupOlivine
PentlanditePerovskitePhosphosideritePrehnitePyritePyrophyllitePyroxeneQuartzRockbridgeiteRocksalt
RutileScheeliteSerpentineSmectite-vermiculiteSphaleriteSpinelStanniteStauroliteStibniteSulphur
TalcTetradymiteTetrahedriteTitaniteTochiliniteTourmalineVesuvianiteVivianiteWollastoniteZircon

161 IMA Minerals at location:
Actinolite  (*)Albite  (*)Almandine  (*)Analcime  (*)Anglesite  (*)
Anhydrite  (*)Ankerite  (*)Anthophyllite  (*)Antigorite  (*)Aragonite  (*)
Arfvedsonite  (*)Arsenopyrite  (*)Augite  (*)Aurichalcite  (*)Autunite  (*)
Awaruite  (*)Azurite  (*)Baryte  (*)Beidellite  (*)Bertrandite  (*)
Beryl  (*)Birnessite  (*)Bornite  (*)Brochantite  (*)Brucite  (*)
Cacoxenite  (*)Calcite  (*)Carrollite  (*)Celestine  (*)Cerussite  (*)
Chabazite-Ca  (*)Chalcanthite  (*)Chalcocite  (*)Chalcopyrite  (*)Chromite  (*)
Chrysocolla  (*)Chrysotile  (*)Clinochlore  (*)Clinoenstatite  (*)Clinozoisite  (*)
Coalingite  (*)Copiapite  (*)Copper  (*)Corundum  (*)Covellite  (*)
Cummingtonite  (*)Cuprite  (*)Desautelsite  (*)Dickite  (*)Diopside  (*)
Dolomite  (*)Dravite  (*)Enstatite  (*)Epidote  (*)Felsőbányaite  (*)
Ferro-hornblende  (*)Fluorapatite  (*)Fluorite  (*)Forsterite  (*)Gahnite  (*)
Galena  (*)Goethite  (*)Gold  (*)Graphite  (*)Grossular  (*)
Gypsum  (*)Harmotome  (*)Heazlewoodite  (*)Hematite  (*)Hemimorphite  (*)
Heulandite-Ca  (*)Hollandite  (*)Huntite  (*)Hydromagnesite  (*)Hydrozincite  (*)
Idaite  (*)Ilmenite  (*)Iron  (*)Jarosite  (*)Kaolinite  (*)
Kyanite  (*)Laumontite  (*)Linnaeite  (*)Lipscombite  (*)Lizardite  (*)
Mackinawite  (*)Magnesio-hornblende  (*)Magnesiochromite  (*)Magnesite  (*)Magnetite  (*)
Malachite  (*)Marcasite  (*)Margarite  (*)Maucherite  (*)Mcguinnessite  (*)
Melanterite  (*)Microcline  (*)Millerite  (*)Molybdenite  (*)Muscovite  (*)
Natrolite  (*)Nimite  (*)Nontronite  (*)Omphacite  (*)Opal  (*)
Orthoclase  (*)Ottrélite  (*)Pargasite  (*)Pentlandite  (*)Phlogopite  (*)
Phosphosiderite  (*)Pokrovskite  (*)Prehnite  (*)Pseudomalachite  (*)Pyrite  (*)
Pyroaurite  (*)Pyrolusite  (*)Pyrophyllite  (*)Pyrrhotite  (*)Quartz  (*)
Riebeckite  (*)Rockbridgeite  (*)Romanèchite  (*)Rosasite  (*)Rutile  (*)
Schorl  (*)Scolecite  (*)Siderite  (*)Siegenite  (*)Sillimanite  (*)
Silver  (*)Smithsonite  (*)Spessartine  (*)Sphalerite  (*)Spinel  (*)
Staurolite  (*)Stibnite  (*)Strontianite  (*)Sulphur  (*)Taenite  (*)
Talc  (*)Tenorite  (*)Tetradymite  (*)Tetrahedrite-(Zn)  (*)Titanite  (*)
Tochilinite  (*)Todorokite  (*)Torbernite  (*)Tremolite  (*)Troilite  (*)
Uraninite  (*)Vermiculite  (*)Vesuvianite  (*)Violarite  (*)Vivianite  (*)
Wollastonite  (*)Wulfenite  (*)Xonotlite  (*)Zaratite  (*)Zircon  (*)
Zoisite  (*)
Mineral nameStructural GroupsIMA FormulaMax Age (Ma)Min Age (Ma)# of Sublocalities containing mineralLOCALITY IDs, not mindat ids# of localities containing mineral
Actinolite  (*)Amphibole   Ca2(Mg4.5-2.5Fe2+0.5-2.5)Si8O22(OH)254044416218394,218401,218403,218472,218495,218613,218633,218641,218672,218725,218775,218806,218823,218851,218895,2189573419
Albite  (*)FeldsparNa(AlSi3O8)774.447023218388,218391,218401,218440,218466,218495,218602,218662,218664,218666,218667,218670,218672,218673,218675,218853,218859,218897,218904,218937,218957,218968,2190168803
Almandine  (*)GarnetFe2+3Al2(SiO4)35104705218388,218391,218401,218601,2189592353
Analcime  (*)AnalcimeNa(AlSi2O6)·H2O3218386,218393,2184951627
Anglesite  (*)BarytePb(SO4)2218691,2186982734
Anhydrite  (*)Not in a structural groupCa(SO4)12183931588
Ankerite  (*)NoneCa(Fe2+,Mg)(CO3)25218388,218794,218826,218950,2189563092
Anthophyllite  (*)Amphibole   Mg2Mg5Si8O22(OH)25104707218400,218401,218472,218795,218828,218851,218957718
Antigorite  (*)Serpentine ClayMg3Si2O5(OH)45104709218402,218433,218669,218791,218797,218803,218806,218823,218957708
Aragonite  (*)AragoniteCa(CO3)5104706218401,218474,218511,218574,218957,2190263250
Arfvedsonite  (*)AmphiboleNaNa2(Fe2+4Fe3+)Si8O22(OH)25404441218641295
Arsenopyrite  (*)ArsenopyriteFeAsS12189509052
Augite  (*)Pyroxene(Ca,Mg,Fe)2Si2O63218393,218495,2186132060
Aurichalcite  (*)None(Zn,Cu)5(CO3)2(OH)62218724,218740919
Autunite  (*)AutuniteCa(UO2)2(PO4)2·10-12H2O3218891,218897,2189681272
Awaruite  (*)Auricupride PerovskiteNi3Fe1218669166
Azurite  (*)Not in a structural groupCu3(CO3)2(OH)254044412218401,218619,218622,218629,218633,218641,218698,218718,218732,218943,218957,2189695509
Baryte  (*)BaryteBa(SO4)10218314,218388,218550,218698,218707,218711,218718,218724,218725,21872911547
Beidellite  (*)Clay Smectite-vermiculite(Na,Ca)0.3Al2(Si,Al)4O10(OH)2·nH2O121867285
Bertrandite  (*)Not in a structural groupBe4Si2O7(OH)21218968606
Beryl  (*)BerylBe3Al2Si6O188218391,218397,218601,218853,218897,218898,218937,2189684286
Birnessite  (*)None(Na,Ca,K)0.6(Mn4+,Mn3+)2O4·1.5H2O1218580178
Bornite  (*)NoneCu5FeS454044418218401,218613,218619,218622,218629,218633,218640,218641,218642,218698,218707,218709,218717,218718,218725,218732,218740,2189575516
Brochantite  (*)BrochantiteCu4(SO4)(OH)62218613,2189571633
Brucite  (*)BruciteMg(OH)25104706218511,218574,218652,218669,218797,218957462
Cacoxenite  (*)NoneFe3+24AlO6(PO4)17(OH)12·75H2O2218388,218987280
Calcite  (*)CalciteCa(CO3)54044452218295,218386,218388,218393,218401,218404,218417,218418,218420,218424,218431,218433,218449,218461,218465,218470,218474,218490,218495,218550,218559,218613,218616,218622,218629,218641,218644,218672,218686,218698,218700,218707,218708,218709,218717,218718,218724,218725,218729,218732,218740,218778,218806,218823,218840,218857,218895,218936,218957,219029,219038,21905927770
Carrollite  (*)SpinelCuCo2S45404446218401,218613,218637,218639,218640,218641154
Celestine  (*)BaryteSr(SO4)12182951252
Cerussite  (*)AragonitePb(CO3)2218691,2186984979
Chabazite-Ca  (*)ChabaziteCa2[Al4Si8O24]·13H2O1218388310
Chalcanthite  (*)ChalcanthiteCu(SO4)·5H2O5404446218401,218613,218633,218641,218698,218718925
Chalcocite  (*)NoneCu2S54044415218401,218613,218622,218629,218637,218641,218707,218708,218709,218717,218718,218725,218732,218740,2189575707
Chalcopyrite  (*)ChalcopyriteCuFeS254044431218388,218389,218401,218404,218465,218495,218608,218613,218616,218619,218622,218629,218637,218639,218640,218641,218698,218717,218718,218724,218725,218732,218740,218778,218806,218823,218840,218857,218950,218957,21896927198
Chromite  (*)SpinelFe2+Cr2O454044439218399,218402,218403,218405,218431,218433,218450,218461,218470,218511,218512,218513,218575,218576,218613,218633,218637,218641,218652,218663,218668,218669,218673,218675,218677,218678,218680,218681,218775,218788,218789,218790,218791,218797,218803,218942,218946,218957,2190163902
Chrysocolla  (*)Allophane(Cu2-xAlx)H2-xSi2O5(OH)4·nH2O5404446218401,218613,218633,218641,218717,2187183531
Chrysotile  (*)Serpentine ClayMg3Si2O5(OH)45104707218402,218433,218669,218775,218797,218823,218957951
Clinochlore  (*)Chlorite ClayMg5Al(AlSi3O10)(OH)851047014218399,218402,218403,218405,218511,218512,218513,218652,218669,218788,218797,218801,218803,2189571756
Clinoenstatite  (*)PyroxeneMg2Si2O6121901694
Clinozoisite  (*)Clinozoisite EpidoteCa2Al3[Si2O7][SiO4]O(OH)5104704218404,218853,218957,2189591025
Coalingite  (*)HydrotalciteMg10Fe3+2(CO3)(OH)24·2H2O121895727
Copiapite  (*)CopiapiteFe2+Fe3+4(SO4)6(OH)2·20H2O1218580382
Copper  (*)CopperCu5404444218593,218691,218943,2190163846
Corundum  (*)CorundumAl2O312185871797
Covellite  (*)CovelliteCuS5404448218401,218613,218622,218637,218641,218691,218707,2189694165
Cummingtonite  (*)Amphibole   Mg2Mg5Si8O22(OH)25104701218401327
Cuprite  (*)Not in a structural groupCu2O5104703218401,218724,2187252970
Desautelsite  (*)HydrotalciteMg6Mn3+2(CO3)(OH)16·4H2O12189579
Dickite  (*)Clay KaoliniteAl2Si2O5(OH)41218314651
Diopside  (*)PyroxeneCaMgSi2O65218465,218550,218778,218853,2189574135
Dolomite  (*)NoneCaMg(CO3)251047019218402,218404,218424,218433,218465,218550,218613,218629,218672,218718,218732,218740,218806,218823,218826,218840,218934,218957,2190599895
Dravite  (*)TourmalineNaMg3Al6(Si6O18)(BO3)3(OH)3(OH)5104706218404,218465,218550,218669,218840,218957648
Enstatite  (*)PyroxeneMg2Si2O65104704218401,218474,218587,218775944
Epidote  (*)Epidote ClinozoisiteCa2(Al2Fe3+)[Si2O7][SiO4]O(OH)1231.544427218300,218388,218391,218393,218397,218401,218404,218440,218466,218495,218587,218608,218613,218633,218641,218698,218718,218722,218778,218785,218835,218859,218913,218936,218943,218957,2189598173
Felsőbányaite  (*)NoneAl4(SO4)(OH)10·4H2O121898366
Ferro-hornblende  (*)Amphibole   Ca2(Fe2+4Al)(Si7Al)O22(OH)25104702218401,218853271
Fluorapatite  (*)ApatiteCa5(PO4)3F4218388,218853,218957,2189682740
Fluorite  (*)FluoriteCaF24218291,218295,218550,2190599617
Forsterite  (*)OlivineMg2(SiO4)2218669,2190161188
Gahnite  (*)SpinelZnAl2O45404446218613,218637,218641,218897,218928,218968445
Galena  (*)RocksaltPbS16218314,218388,218550,218616,218622,218698,218700,218703,218717,218724,218740,218857,218950,218951,218957,21895924243
Goethite  (*)DiasporeFeO(OH)54044419218314,218370,218375,218418,218420,218426,218469,218490,218510,218595,218613,218624,218641,218696,218731,218786,218950,218952,2189577437
Gold  (*)CopperAu1231.544419218394,218613,218640,218641,218718,218725,218830,218923,218930,218933,218934,218941,218948,218949,218950,218951,218953,218955,21895630554
Graphite  (*)NoneC5104703218404,218465,2185502812
Grossular  (*)GarnetCa3Al2(SiO4)312189571544
Gypsum  (*)GypsumCa(SO4)·2H2O51047010218388,218401,218686,218983,218984,218997,219002,219013,219014,2190156890
Harmotome  (*)HarmotomeBa2(Si12Al4)O32·12H2O1218388290
Heazlewoodite  (*)NoneNi3S21218669205
Hematite  (*)CorundumFe2O354044432218291,218302,218303,218314,218356,218364,218375,218388,218417,218580,218595,218608,218613,218622,218633,218637,218641,218696,218698,218707,218718,218724,218725,218786,218897,218903,218936,218943,218957,218973,218997,21900314640
Hemimorphite  (*)Not in a structural groupZn4(Si2O7)(OH)2·H2O2218724,2187401689
Heulandite-Ca  (*)Heulandite(Ca,Na,K)5(Si27Al9)O72·26H2O1218388246
Hollandite  (*)CoronaditeBa(Mn4+6Mn3+2)O161218580243
Huntite  (*)Not in a structural groupCaMg3(CO3)4121895769
Hydromagnesite  (*)NoneMg5(CO3)4(OH)2·4H2O5104704218403,218574,218669,218957341
Hydrozincite  (*)NoneZn5(CO3)2(OH)62218622,2187401066
Idaite  (*)Stannite SphaleriteCu3FeS45404441218641142
Ilmenite  (*)CorundumFe2+Ti4+O312218388,218393,218495,218581,218587,218613,218659,218826,218827,218903,218950,2189575433
Iron  (*)IronFe12190161089
Jarosite  (*)AluniteKFe3+3(SO4)2(OH)612189842228
Kaolinite  (*)Clay KaoliniteAl2Si2O5(OH)43218489,218495,2189835591
Kyanite  (*)Not in a structural groupAl2OSiO43218587,218844,2188781507
Laumontite  (*)Not in a structural groupCaAl2Si4O12·4H2O5104709218388,218393,218401,218474,218495,218559,218778,218785,2189361271
Linnaeite  (*)SpinelCo2+Co3+2S45404444218613,218633,218637,218641249
Lipscombite  (*)LipscombiteFe2+Fe3+2(PO4)2(OH)2121898747
Lizardite  (*)Serpentine ClayMg3Si2O5(OH)42218433,218957359
Mackinawite  (*)None(Fe,Ni)1+xS (x = 0-0.07)1218840451
Magnesio-hornblende  (*)Amphibole   Ca2(Mg4Al)(Si7Al)O22(OH)21218957238
Magnesiochromite  (*)SpinelMgCr2O42218669,218942311
Magnesite  (*)CalciteMg(CO3)51047020218402,218403,218405,218431,218433,218511,218512,218513,218652,218669,218672,218673,218795,218797,218801,218806,218823,218940,218942,2189571487
Magnetite  (*)SpinelFe2+Fe3+2O454044444218388,218397,218400,218401,218402,218405,218433,218450,218472,218495,218535,218575,218576,218587,218608,218613,218616,218619,218633,218637,218639,218640,218641,218642,218648,218681,218718,218722,218780,218792,218794,218801,218813,218823,218826,218827,218889,218890,218893,218895,218940,218949,218950,21895714899
Malachite  (*)MalachiteCu2(CO3)(OH)254044423218401,218613,218616,218619,218622,218629,218633,218641,218642,218644,218698,218707,218717,218718,218724,218725,218732,218740,218840,218943,218950,218957,21896912537
Marcasite  (*)MarcasiteFeS211218314,218356,218364,218388,218393,218489,218495,218580,218973,218997,2190035674
Margarite  (*)Mica ClayCaAl2Si2Al2O10(OH)22218550,218669168
Maucherite  (*)NoneNi11As81218669161
Mcguinnessite  (*)MalachiteCuMg(CO3)(OH)2121895734
Melanterite  (*)MelanteriteFe(SO4)·7H2O5104704218342,218388,218401,218613915
Microcline  (*)FeldsparK(AlSi3O8)774.447022218388,218389,218397,218401,218404,218417,218420,218440,218465,218466,218471,218473,218550,218832,218833,218853,218859,218873,218897,218903,218904,2189684924
Millerite  (*)MilleriteNiS4218314,218513,218669,2189571066
Molybdenite  (*)MolybdeniteMoS2774.4514.65218388,218466,218495,218630,2189575800
Muscovite  (*)Mica ClayKAl2(Si3Al)O10(OH)2774.447039218388,218389,218397,218404,218457,218465,218466,218471,218473,218495,218535,218550,218601,218602,218613,218644,218652,218722,218725,218832,218833,218840,218853,218859,218860,218873,218878,218885,218889,218890,218897,218898,218903,218904,218937,218942,218951,218968,21896917380
Natrolite  (*)NatroliteNa2(Si3Al2)O10·2H2O2218393,2184951236
Nimite  (*)Chlorite Clay(Ni,Mg,Al)6(Si,Al)4O10(OH)8121895715
Nontronite  (*)Clay Smectite-vermiculiteNa0.3Fe3+2(Si,Al)4O10(OH)2·nH2O1218858471
Omphacite  (*)Pyroxene(Ca,Na)(Mg,Fe,Al)Si2O61218957229
Opal  (*)AmorphousSiO2·nH2O51047010218402,218405,218431,218433,218586,218672,218806,218823,218957,2189692994
Orthoclase  (*)FeldsparK(AlSi3O8)3218440,218725,2188592349
Ottrélite  (*)ChloritoidMn2+Al2O(SiO4)(OH)2121871759
Pargasite  (*)AmphiboleNaCa2(Mg4Al)(Si6Al2)O22(OH)21218957313
Pentlandite  (*)Pentlandite(Ni,Fe)9S82218957,2190161512
Phlogopite  (*)Mica ClayKMg3(AlSi3O10)(OH)25104708218404,218424,218449,218465,218550,218840,218853,2188752273
Phosphosiderite  (*)PhosphosideriteFe3+(PO4)·2H2O1218987182
Pokrovskite  (*)MalachiteMg2(CO3)(OH)212189579
Prehnite  (*)PrehniteCa2Al(Si3Al)O10(OH)23218495,218936,2189571898
Pseudomalachite  (*)NoneCu5(PO4)2(OH)41218613369
Pyrite  (*)PyriteFeS21231.544456218314,218342,218388,218391,218393,218397,218401,218404,218465,218466,218474,218495,218550,218559,218608,218613,218619,218624,218630,218639,218640,218641,218659,218669,218672,218698,218703,218717,218718,218725,218740,218775,218778,218785,218806,218823,218826,218827,218840,218857,218878,218895,218903,218913,218930,218934,218949,218950,218951,218952,218953,218956,218957,218959,218969,21897039462
Pyroaurite  (*)HydrotalciteMg6Fe3+2(CO3)(OH)16·4H2O121866989
Pyrolusite  (*)RutileMnO23218691,218918,2190333106
Pyrophyllite  (*)Clay PyrophylliteAl2Si4O10(OH)21218903771
Pyrrhotite  (*)NickelineFe7S85104709218404,218465,218474,218495,218550,218840,218853,218950,2189579056
Quartz  (*)QuartzSiO21231.5444107218314,218388,218391,218393,218394,218397,218399,218401,218402,218404,218405,218417,218420,218424,218430,218433,218440,218461,218465,218469,218470,218471,218473,218490,218495,218511,218513,218535,218550,218559,218601,218602,218608,218613,218619,218622,218629,218630,218633,218641,218642,218644,218652,218659,218661,218669,218672,218682,218691,218698,218703,218707,218708,218709,218718,218722,218724,218725,218732,218740,218775,218785,218786,218794,218797,218806,218823,218832,218833,218835,218840,218845,218846,218853,218857,218859,218860,218873,218878,218885,218889,218890,218897,218900,218903,218904,218913,218923,218931,218932,218934,218949,218950,218951,218952,218953,218956,218957,218959,218968,218969,218970,218997,219003,219040,219056,21905961156
Riebeckite  (*)Amphibole   Na2(Fe2+3Fe3+2)Si8O22(OH)25404441218641375
Rockbridgeite  (*)Rockbridgeite(Fe2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)51218987206
Romanèchite  (*)None(Ba,H2O)2(Mn4+,Mn3+)5O101218580312
Rosasite  (*)MalachiteCuZn(CO3)(OH)21218724454
Rutile  (*)RutileTiO251047013218388,218404,218433,218465,218495,218550,218581,218587,218826,218827,218840,218942,2189575614
Schorl  (*)TourmalineNaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)774.447029218388,218393,218397,218401,218404,218417,218424,218457,218465,218466,218471,218490,218495,218602,218682,218832,218833,218860,218873,218876,218885,218897,218900,218903,218937,218950,218956,218959,2189682705
Scolecite  (*)NatroliteCa(Si3Al2)O10·3H2O2218495,218778390
Siderite  (*)CalciteFe(CO3)774.444422218304,218314,218319,218335,218356,218387,218388,218394,218396,218445,218466,218613,218633,218641,218754,218758,218772,218773,218940,218973,218997,2190036417
Siegenite  (*)SpinelCoNi2S45404442218613,218635249
Sillimanite  (*)Not in a structural groupAl2SiO512188441516
Silver  (*)CopperAg2218725,2189505186
Smithsonite  (*)CalciteZn(CO3)5218593,218622,218698,218724,2187402473
Spessartine  (*)GarnetMn2+3Al2(SiO4)34218601,218835,218897,2189281214
Sphalerite  (*)SphaleriteZnS54044414218314,218388,218404,218550,218613,218616,218622,218637,218698,218700,218717,218724,218740,21895021482
Spinel  (*)SpinelMgAl2O43218587,218613,2190161934
Staurolite  (*)StauroliteFe2+2Al9Si4O23(OH)5104707218388,218399,218535,218587,218775,218878,218959978
Stibnite  (*)StibniteSb2S312184333418
Strontianite  (*)AragoniteSr(CO3)3218295,218725,219038589
Sulphur  (*)SulphurS12186982045
Taenite  (*)None(Ni,Fe)1219016703
Talc  (*)Clay TalcMg3Si4O10(OH)254044443218391,218400,218401,218403,218404,218405,218461,218465,218470,218472,218495,218511,218550,218574,218613,218633,218641,218642,218662,218669,218671,218672,218675,218703,218775,218794,218795,218797,218798,218801,218806,218823,218826,218827,218840,218875,218877,218940,218942,218943,218950,218956,2189573337
Tenorite  (*)NoneCuO5218613,218619,218622,218718,2187401101
Tetradymite  (*)TetradymiteBi2Te2S2218918,218949510
Tetrahedrite-(Zn)  (*)TetrahedriteCu6(Cu4Zn2)Sb4S1312187185317
Titanite  (*)TitaniteCaTi(SiO4)O1231.547012218388,218404,218495,218550,218587,218725,218785,218853,218895,218913,218950,2189574899
Tochilinite  (*)Tochilinite6(Fe0.9S)·5[(Mg,Fe)(OH)2]121895756
Todorokite  (*)None(Na,Ca,K,Ba,Sr)1-x(Mn,Mg,Al)6O12·3-4H2O2218580,218616433
Torbernite  (*)NoneCu(UO2)2(PO4)2·12H2O12189691059
Tremolite  (*)Amphibole   Ca2(Mg5.0-4.5Fe2+0.0-0.5)Si8O22(OH)251047017218401,218404,218417,218418,218419,218420,218424,218449,218465,218472,218550,218593,218613,218828,218840,218875,2189572562
Troilite  (*)NoneFeS12190161044
Uraninite  (*)FluoriteUO212189692718
Vermiculite  (*)Clay Smectite-vermiculiteMg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4·8H2O6218449,218474,218672,218794,218795,218875652
Vesuvianite  (*)Vesuvianite(Ca,Na)19(Al,Mg,Fe)13(SiO4)10(Si2O7)4(OH,F,O)1012189571395
Violarite  (*)SpinelFeNi2S45404442218613,218635380
Vivianite  (*)VivianiteFe2+3(PO4)2·8H2O4218355,218370,218591,219002636
Wollastonite  (*)WollastoniteCaSiO32218424,2185501247
Wulfenite  (*)ScheelitePbMoO42218644,2187051655
Xonotlite  (*)NoneCa6Si6O17(OH)21218957109
Zaratite  (*)AmorphousNi3(CO3)(OH)4·4H2O2218652,21866956
Zircon  (*)ZirconZr(SiO4)9218440,218581,218587,218601,218782,218826,218827,218835,2188595251
Zoisite  (*)EpidoteCa2Al3[Si2O7][SiO4]O(OH)5404449218391,218393,218495,218559,218593,218613,218633,218950,2189571025


19 Ages assigned to this locality:

Excel IDMax Age (Ma)Min Age (Ma)Age as listed in referenceDating MethodAge InterpretPrioritized?Sample SourceSample NumRun NumAge from other LocalityDated MineralMinerals explicitely stated as having this ageAge applies to these ElementsMinDat Locality IDDated Locality (Max Age)Location as listed in referenceReferenceReference DOIReference IDAge Notes
podchrome-00496510470Lower Ordovician (490±20 Ma)       Cr3822Bare Hills, Baltimore Co., Maryland, USABare HillsMoiser et al. (2012) USGSSIR2012_5157 
podchrome-00501510470Lower Ordovician (490±20 Ma)       Cr142886Harris Mine, Baltimore Co., Maryland, USAHarrisMoiser et al. (2012) USGSSIR2012_5157 
USGS-U-Th-Pb-00759_206_238585.8555.8570.8±15206_238 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00759_207_206544.6514.6529.6±15207_206 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00759_207_235577.6547.6562.6±15207_235 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00760_206_238774.4744.4759.4±15206_238 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00760_207_206636.7606.7621.7±15207_206 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00760_207_235740.4710.4725.4±15207_235 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00761_206_238749.6719.6734.6±15206_238 zircon   Zircon  142896Hilton Quarry, Baltimore Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
podchrome-00500510470Lower Ordovician (490±20 Ma)       Cr42105Weir Mine, Holbrook, Baltimore Co., Maryland, USAWeirMoiser et al. (2012) USGSSIR2012_5157 
podchrome-00495510470Lower Ordovician (490±20 Ma)       Cr28369Choate Mine, Owings Mills, Baltimore Co., Maryland, USAChoateMoiser et al. (2012) USGSSIR2012_5157 
Emily000556540444Cambrian-Ordovician        24179Sykesville, Carroll Co., Maryland, USASykesvilleRast and Horton (1989)10.1130/SPE228-p1GSA288_1 
Emily000557488470479±9  zircon   ZirconZircon 24179Sykesville, Carroll Co., Maryland, USASykesvilleHorton et al. (2010)10.1130/2010.1206(25)GSA206_621 
podchrome-00407490490Lower Ordovician (490±20 Ma)       Cr142724Ayres Mine, Jarretsville-Dublin District, Harford Co., Maryland, USAAyresMoiser et al. (2012) USGSSIR2012_5157 
podchrome-00502510470Lower Ordovician (490±20 Ma)       Cr142771Cherry Hill Mine, Jarretsville-Dublin District, Harford Co., Maryland, USACherry HillMoiser et al. (2012) USGSSIR2012_5157 
podchrome-00497510470Lower Ordovician (490±20 Ma)       Cr143059Reed Mine, Jarretsville-Dublin District, Harford Co., Maryland, USAReedMoiser et al. (2012) USGSSIR2012_5157 
USGS-U-Th-Pb-00758_206_238968938953±15206_238 zircon   Zircon  43888Woodstock, Howard Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00758_207_2061231.51201.51216.5±15207_206 zircon   Zircon  43888Woodstock, Howard Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 
USGS-U-Th-Pb-00758_207_2351051.31021.31036.3±15207_235 zircon   Zircon  43888Woodstock, Howard Co., Maryland, USA USGS-U-Th-Pb USGS-U-Th-Pb 

SampleSource LocalityReference URL
R060796Line Pit (Lowe's Mine), State Line District, Cecil Co., Maryland, USAhttps://rruff.info/R060796
R040063Harford Co., Maryland, USAhttps://rruff.info/R040063
R110197Hunting Hill Quarry (Rockville Crushed Stone Quarry; Travilah Quarry; Rockville Quarry; Bardon Stone Quarry; Aggregate Industries Quarry), Rockville, Montgomery Co., Maryland, USAhttps://rruff.info/R110197

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