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In the late medieval and early modern eras, the word "marcasite" meant all iron sulfides in general, including both pyrite and the mineral marcasite. The narrower, modern scientific definition for marcasite as specifically orthorhombic iron sulfide dates from 1845. Jewellery where
493:, where it forms as sharp individual crystals and crystal groups, and nodules (similar to those shown here). Marcasite is also found in complex sulphide deposits. In the ReocĂn mine, Cantabria, Spain, appears as crystals grouped in the form of
363:. It tarnishes to a yellowish or brownish color and gives a black streak. It is a brittle material that cannot be scratched with a knife. The thin, flat, tabular crystals, when joined in groups, are called "cockscombs".
689:
oxidizing and combining with water to produce sulfuric acid that attacks other sulfide minerals and mineral labels. Low humidity (less than 60%) storage conditions prevents or slows the reaction.
375:; a term which pre-dates the scientific definition, using the original sense of the word. Marcasite in the scientific sense is not used as a gem due to its brittleness.
695:
719:
1071:
528:
calculations suggest that this is due to pyrite having a higher surface energy (thus being less thermodynamically stable) than marcasite at low pH.
539:
of those rocks. However, sedimentary pore waters below the modern ocean are typically buffered at near-neutral to slightly alkaline pH by dissolved
179:
Crystals typically tabular on {010}, curved faces common; stalactitic, reniform, massive; cockscomb and spearhead shapes due to twinning on {101}.
543:
species. This raises the question of how sedimentary pore waters became sufficiently acidic to promote marcasite formation in the past.
1264:
707:
525:
282:
creamy white; light yellowish white; white with rose-brown tint. Anisotropism: Very strong, yellow through pale green to dark green
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infiltrating from the overlying water column, and rapid anoxic organic matter decomposition and organic acid generation by
257:
1072:"Marcasite in Black Shales—a Mineral Proxy for Oxygenated Bottom Waters and Intermittent Oxidation of Carbonaceous Muds"
1249:
1028:
658:
Marcasite reacts more readily than pyrite under conditions of high humidity. The product of this disintegration is
399:
Marcasite can be formed as both a primary or a secondary mineral. It typically forms under low-temperature, highly
392:
1244:
1037:
792:
599:
variety of marcasite, found at
Churprinz Friedrich August Erbstolln Mine (Kurprinz Mine), GroĂźschirma Freiberg,
638:: designates a marcasite having twin spearhead crystal on {101}. Sperkise derives from the German Speerkies (
685:". When a specimen goes through pyrite decay, the marcasite reacts with moisture and oxygen in the air, the
646:
gravel or stone). This twin is very common in the marcasite of a chalky origin, particularly those from the
78:
1194:
1114:"Shifting modes of iron sulfidization at the onset of OAE-2 drive regional shifts in pyrite δ34S records"
531:
Due to the association of marcasite with low pH, the occurrence of marcasite in sedimentary rocks in the
969:
546:
Several theories have been proposed for the formation of early diagenetic marcasite, including: partial
383:
214:
204:
1127:
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1041:
978:
937:
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551:
323:
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As a secondary mineral, it forms by chemical alteration of a primary mineral, such as pyrrhotite or
1269:
372:
360:
247:
237:
1145:
774:
447:
194:
504:
Marcasite crystals forming a cockscomb-shaped aggregate. ReocĂn Mine, ReocĂn, Cantabria (Spain).
1174:
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1004:
902:
592:
353:
137:
20:
1135:
1118:
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994:
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901:] (in Spanish). Vitoria, Spain: Museo de Ciencias Naturales de Alava. pp. 489–490.
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404:
267:
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61:
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Tin-white on fresh surface, pale bronze-yellow, darkening on exposure, iridescent tarnish
1131:
1090:
1045:
982:
965:"Evaluating structure selection in the hydrothermal growth of FeS2 pyrite and marcasite"
941:
813:
760:
457:
As a primary mineral marcasite forms nodules, concretions, and crystals in a variety of
999:
964:
559:
423:
98:
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1238:
1220:
1149:
1112:
Bryant, R. N.; Jones, C.; Raven, M. R.; Owens, J. D.; Fike, D. A. (20 October 2020).
949:
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663:
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600:
486:
482:
174:
110:
1219:. How Minerals Form and Change. Warsaw, Poland: University of Warsaw. Archived from
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420:
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than pyrite. Specimens of marcasite often crumble and break up due to the unstable
307:
156:
103:
1140:
1113:
667:
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implies the presence of highly acidic conditions during the formation and early
349:
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On fresh surfaces, it is pale yellow to almost white and has a bright metallic
1054:
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536:
439:
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117:
855:
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Massive aggregate (c. 9 Ă— 7 Ă— 5.5 cm) of marcasite from the steep coast near
873:
547:
540:
412:
1008:
666:. The hydrous iron sulfate forms a white powder consisting of the mineral
35:
520:
In laboratory experiments, marcasite forms preferentially to pyrite at a
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This disintegration of marcasite in mineral collections is known as "
604:
574:
490:
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342:
878:
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Iridescent cluster of marcasite crystals (3.3 Ă— 2.1 Ă— 1.4 cm)
499:
470:
462:
408:
382:
474:
416:
400:
1024:"pH BUFFERING OF PORE WATER OF RECENT ANOXIC MARINE SEDIMENTS"
330:
627:
metalonchidite (Sandberger) described at
Bernhard Mine near
577:
variety of marcasite, found in
Denison Drury and Townships,
895:
Minerales y Minas de España. Vol. II. Sulfuros y sulfosales
521:
318:. It is physically and crystallographically distinct from
1200:. Conserv-O-Gram. U.S. National Park Service. April 1998.
963:
Kitchaev, Daniil A.; Ceder, Gerbrand (14 December 2016).
16:
Iron disulfide (FeS2) with orthorhombic crystal structure
19:
This article is about the mineral. For the jewelry, see
899:
Minerals and Mines of Spain. Sulphides and sulphosalts.
924:"Marcasite precipitation from hydrothermal solutions"
922:
Murowchick, James B.; Barnes, H. L. (December 1986).
713:
Two halves of a ball of marcasite geode from France
286:
276:
266:
256:
246:
236:
223:
213:
203:
193:
189:
Common and repeated on {101}; less common on {011}.
183:
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136:
124:
109:
97:
87:
77:
60:
50:
45:
28:
1070:
199:Cleavage: {101}, rather distinct; {110} in traces
1163:Klein, Cornelis; Hurlbut, Cornelius S. (1985).
333:, having a short bonding distance between the
1195:"Storage Concerns for Geological Collections"
8:
808:
806:
337:atoms. The structures differ in how these
1211:Parafiniuk, J.; Stepisiewicz, M. (2000).
1139:
1053:
998:
768:
326:. Both structures contain the disulfide S
1213:"Pyrite oxidation under room conditions"
832:
830:
735:
691:
426:. Commonly associated minerals include
25:
7:
952:– via Elsevier Science Direct.
745:"IMA–CNMNC approved mineral symbols"
40:Marcasite with tarnish (8Ă—6 cm)
607:, Germany; ideal formula Fe(S, As)
465:layers found on both sides of the
371:is used as the gemstone is called
14:
1069:Schieber, Juergen (1 July 2011).
146:c = 3.381 Ă…; Z = 2
1169:(20th ed.). Wiley. p.
1022:Ben-Yaakov, Sam (January 1973).
718:
706:
694:
516:Sedimentary marcasite and low pH
419:) as well as in low temperature
348:. Marcasite is lighter and more
272:4.875 calculated, 4.887 measured
34:
1078:Journal of Sedimentary Research
929:Geochimica et Cosmochimica Acta
893:Calvo Rebollar, Miguel (2003).
316:orthorhombic crystal structure
1:
1141:10.1016/j.chemgeo.2020.119808
322:, which is iron sulfide with
1101:– via GeoScienceWorld.
950:10.1016/0016-7037(86)90214-0
614:Synonyms for this variety:
1286:
1265:Minerals in space group 58
1038:John Wiley & Sons, Ltd
1029:Limnology and Oceanography
393:Mecklenburg-West Pomerania
18:
1055:10.4319/lo.1973.18.1.0086
403:conditions. It occurs in
33:
341:are arranged around the
725:Marcasite with dolomite
324:cubic crystal structure
821:Handbook of Mineralogy
749:Mineralogical Magazine
524:of less than about 5.
505:
396:
1260:Orthorhombic minerals
1255:Alchemical substances
970:Nature Communications
550:of primary pyrite by
503:
386:
89:Strunz classification
1223:on 24 November 2006.
1166:Manual of Mineralogy
566:Varieties and blends
302:, sometimes called "
1132:2020ChGeo.55319808B
1099:10.2110/jsr.2011.41
1091:2011JSedR..81..447S
1046:1973LimOc..18...86B
991:10.1038/ncomms13799
983:2016NatCo...713799K
942:1986GeCoA..50.2615M
770:10.1180/mgm.2021.43
761:2021MinM...85..291W
743:Warr, L.N. (2021).
373:marcasite jewellery
252:Dark-grey to black.
642:meaning spear and
506:
397:
144:b = 5.414 Ă…,
142:a = 4.436 Ă…,
115:Dipyramidal (mmm)
1250:Iron(II) minerals
1217:www.geo.uw.edu.pl
936:(12): 2615–2629.
631:(Baden), Germany.
593:August Breithaupt
461:, such as in the
405:sedimentary rocks
354:crystal structure
304:white iron pyrite
293:
292:
161:119.98 g/mol
21:Marcasite jewelry
1277:
1245:Sulfide minerals
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1119:Chemical Geology
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660:iron(II) sulfate
579:Sudbury District
552:molecular oxygen
459:sedimentary rock
268:Specific gravity
229:
209:Irregular/Uneven
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66:(repeating unit)
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467:English Channel
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120:: (2/m 2/m 2/m)
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55:Sulfide mineral
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1231:External links
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111:Crystal class
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1221:the original
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977:(1): 13799.
974:
968:
958:
933:
927:
917:
898:
894:
888:
882:(in French).
877:
874:"marcassite"
868:
859:
850:
841:
820:
799:(in German).
796:
787:
752:
748:
738:
683:pyrite decay
682:
680:
657:
643:
639:
635:
634:
624:lonchandite,
613:
588:
587:
570:
569:
556:fermentation
545:
530:
519:
510:chalcopyrite
507:
494:
456:
421:hydrothermal
398:
389:KĂĽhlungsborn
365:
358:
308:iron sulfide
303:
299:
294:
157:Formula mass
130:
104:Orthorhombic
1215:. Geology.
856:"Marcasite"
838:"Marcasite"
814:"Marcasite"
793:"Marcasite"
668:melanterite
618:kausimkies,
278:Pleochroism
258:Diaphaneity
126:Space group
1270:Disulfides
1239:Categories
1126:: 119808.
860:Webmineral
842:Mindat.org
731:References
589:Lonchidite
585:, Canada.
537:diagenesis
495:cockscombs
440:sphalerite
432:pyrrhotite
413:limestones
379:Occurrence
287:References
225:Mohs scale
118:H-M symbol
79:IMA symbol
1150:224938768
1040:: 86–94.
779:235729616
621:kyrosite,
548:oxidation
541:carbonate
526:Ab initio
481:, and at
395:, Germany
339:di-anions
300:marcasite
138:Unit cell
29:Marcasite
1009:27966547
636:Sperkise
448:dolomite
444:fluorite
242:Metallic
228:hardness
215:Tenacity
205:Fracture
195:Cleavage
185:Twinning
93:2.EB.10a
51:Category
1128:Bibcode
1087:Bibcode
1042:Bibcode
1000:5171653
979:Bibcode
938:Bibcode
862:. data.
844:. 2571.
757:Bibcode
629:Hausach
597:Arsenic
583:Ontario
571:Blueite
479:England
452:calcite
350:brittle
346:cations
314:) with
297:mineral
219:Brittle
62:Formula
46:General
1177:
1148:
1007:
997:
905:
777:
687:sulfur
670:, FeSO
605:Saxony
575:Nickel
491:France
450:, and
436:galena
428:pyrite
409:shales
401:acidic
369:pyrite
361:luster
335:sulfur
320:pyrite
306:", is
262:Opaque
248:Streak
238:Luster
1198:(PDF)
1146:S2CID
1036:(1).
897:[
879:CNRTL
817:(PDF)
775:S2CID
654:Decay
640:Speer
471:Dover
463:chalk
424:veins
417:coals
232:6–6.5
166:Color
1175:ISBN
1005:PMID
903:ISBN
662:and
644:Kies
562:.
558:and
475:Kent
310:(FeS
295:The
131:Pnnm
1171:286
1136:doi
1124:553
1095:doi
1050:doi
995:PMC
987:doi
946:doi
765:doi
678:O.
674:·7H
595:):
469:at
331:ion
83:Mrc
70:FeS
1241::
1173:.
1144:.
1134:.
1122:.
1116:.
1093:.
1083:81
1081:.
1075:.
1048:.
1034:18
1032:.
1026:.
1003:.
993:.
985:.
973:.
967:.
944:.
934:20
932:.
926:.
876:.
858:.
840:.
829:^
819:.
805:^
795:.
773:.
763:.
753:85
751:.
747:.
650:.
611:.
603:,
581:,
522:pH
512:.
497:.
489:,
485:,
477:,
473:,
454:.
446:,
442:,
438:,
434:,
430:,
411:,
391:,
356:.
343:Fe
1183:.
1152:.
1138::
1130::
1097::
1089::
1058:.
1052::
1044::
1011:.
989::
981::
975:7
948::
940::
911:.
781:.
767::
759::
676:2
672:4
609:2
591:(
407:(
328:2
312:2
72:2
23:.
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