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299:
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256:, are much less common.) Their structure consists of parallel chains of negatively-charged silica tetrahedra bonded together by metal cations. In other words, each silicon ion in a pyroxene crystal is surrounded by four oxygen ions forming a tetrahedron around the relatively small silicon ion. Each silicon ion shares two oxygen ions with neighboring silicon ions in the chain.
459:
Magnesium, calcium and iron are by no means the only cations that can occupy the X and Y sites in the pyroxene structure. A second important series of pyroxene minerals are the sodium-rich pyroxenes, corresponding to the 'pyroxene triangle' nomenclature. The inclusion of sodium, which has a charge of
318:
and the names of the pyroxene minerals are primarily defined by their chemical composition. Pyroxene minerals are named according to the chemical species occupying the X (or M2) site, the Y (or M1) site, and the tetrahedral T site. Cations in Y (M1) site are closely bound to 6 oxygens in octahedral
259:
The tetrahedra in the chain all face in the same direction, so that two oxygen ions are located on one face of the chain for every oxygen ion on the other face of the chain. The oxygen ions on the narrower face are described as apical oxygen ions. Pairs of chains are bound together on their apical
639:
In assigning ions to sites, the basic rule is to work from left to right in this table, first assigning all silicon to the T site and then filling the site with the remaining aluminium and finally iron(III); extra aluminium or iron can be accommodated in the Y site and bulkier ions on the X site.
319:
coordination. Cations in the X (M2) site can be coordinated with 6 to 8 oxygen atoms, depending on the cation size. Twenty mineral names are recognised by the
International Mineralogical Association's Commission on New Minerals and Mineral Names and 105 previously used names have been discarded.
406:) only crystallises in the monoclinic system. There is not complete solid solution in calcium content and Mg-Fe-Ca pyroxenes with calcium contents between about 15 and 25 mol.% are not stable with respect to a pair of exolved crystals. This leads to a
298:
264:. The I-beams interlock, with additional X cations bonding the outer faces of the I-beams to neighboring I-beams and providing the remaining charge balance. This binding is relatively weak and gives pyroxenes their characteristic
468:
this is added by the inclusion of a +3 cation (aluminium and iron(III) respectively) on the Y site. Sodium pyroxenes with more than 20 mol.% calcium, magnesium or iron(II) components are known as
1238:"Mineral Lamination Development in Layered Gabbros of the British Palaeogene Igneous Province: A Combined Anisotropy of Magnetic Susceptibility, Quantitative Textural and Mineral Chemistry Study"
437:) solid solution. The divide is taken at >45 mol.% Ca. As the calcium ion cannot occupy the Y site, pyroxenes with more than 50 mol.% calcium are not possible. A related mineral
217:; it was assumed they were impurities in the glass, hence the name meaning "fire stranger". However, they are simply early-forming minerals that crystallized before the lava erupted.
357:
A typical pyroxene has mostly silicon in the tetrahedral site and predominately ions with a charge of +2 in both the X and Y sites, giving the approximate formula
1306:
304:
Structure of pyroxene looking along the silica chains. "I-beams" are outlined in green. Silicon ions are oversized to emphasize the silicon chains.
643:
Not all the resulting mechanisms to achieve charge neutrality follow the sodium example above, and there are several alternative schemes:
260:
sides by Y cations, with each Y cation surrounded by six oxygen ions. The resulting pairs of single chains have sometimes been likened to
150:, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica
1379:
1189:
Deegan, Frances M.; Whitehouse, Martin J.; Troll, Valentin R.; Budd, David A.; Harris, Chris; Geiger, Harri; Hålenius, Ulf (2016-12-30).
1401:
391:
clinoenstatite (and the ferrosilite equivalents). Increasing the calcium content prevents the formation of the orthorhombic phases and
274:
664:
Coupled substitution of a 1+ ion on the X site and a mixture of equal numbers of 2+ and 4+ ions on the Y site. This leads to
286:
252:
Pyroxenes are the most common single-chain silicate minerals. (The only other important group of single-chain silicates, the
745:
crystals, and rare grass-green diopside grains. The fine-grained gray rock in this image is the host basalt.(unknown scale).
1431:
484:
1289:
1191:"Pyroxene standards for SIMS oxygen isotope analysis and their application to Merapi volcano, Sunda arc, Indonesia"
142:(V) or even iron (Fe(II) or Fe(III)). Although aluminium substitutes extensively for silicon in silicates such as
1153:
195:
17:
368:. The names of the common calcium–iron–magnesium pyroxenes are defined in the 'pyroxene quadrilateral'. The
1483:
1339:
1321:
1305:
Morimoto, N.; Fabries, J.; Ferguson, A.K.; Ginzburg, I.V.; Ross, M.; Seifeit, F.A.; Zussman, J. (1989).
737:
from San Carlos Indian
Reservation, Gila Co., Arizona, USA. The xenolith is dominated by green peridot
515:
A wide range of other cations that can be accommodated in the different sites of pyroxene structures.
314:
The chain silicate structure of the pyroxenes offers much flexibility in the incorporation of various
1190:
460:+1, into the pyroxene implies the need for a mechanism to make up the "missing" positive charge. In
479:
476:. With 80% or more of these components the pyroxene is classified using the quadrilateral diagram.
54:
1598:
1603:
1424:
183:
1593:
1471:
650:
of 1+ and 3+ ions on the X and Y sites respectively. For example, Na and Al give the jadeite
265:
1202:
647:
456:) but important structural differences mean that it is instead classified as a pyroxenoid.
221:
8:
1395:
1206:
1554:
689:
The
Tschermak substitution where a 3+ ion occupies the Y site and a T site leading to
1417:
1363:
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68:
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1161:– sometimes substituted in jewelry by hiddenite, a green variety of spodumene.
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749:
711:
338:
Pyroxene quadrilateral nomenclature of the calcium, magnesium, iron pyroxenes
178:
1236:
O’Driscoll, Brian; Stevenson, Carl T. E.; Troll, Valentin R. (2008-05-15).
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In nature, more than one substitution may be found in the same mineral.
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compositions. There is an arbitrary separation between augite and the
388:
253:
210:
155:
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383:, contains up to 5 mol.% calcium and exists in three polymorphs,
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Group of inosilicate minerals with single chains of silica tetrahedra
723:
1340:"NASA Rover's First Soil Studies Help Fingerprint Martian Minerals"
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123:
87:
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A single chain of silicon tetrahedra viewed in the direction
205:). Pyroxenes were so named due to their presence in volcanic
292:
A single chain of silica tetrahedra viewed in the direction
1513:
1409:
1343:
206:
99:
91:
1188:
761:
from Mars), a rock consisting mostly of pyroxene minerals
1367:. eds. A. Jorgensen, C. Cleveland. Encyclopedia of Earth
1235:
1070:
Eulite, intermediate between hypersthene and ferrosilite
441:
has the formula of the hypothetical calcium end member (
350:
Pyroxene triangle nomenclature of the sodium pyroxenes
1135:
1369:. National Council for Science and the Environment.
1405:. Vol. 22 (11th ed.). 1911. p. 696.
1284:. New York: Oxford University Press. p. 261.
110:, and Y represents ions of smaller size, such as
1585:
1055:, intermediate between enstatite and hypersthene
1275:
1273:
1425:
309:
1331:
1270:
520:Order of cation occupation in the pyroxenes
379:) includes the common rock-forming mineral
1432:
1418:
1253:
748:
741:, together with black orthopyroxene and
722:
710:
478:
53:) are a group of important rock-forming
29:
14:
1586:
387:orthoenstatite and protoenstatite and
71:. Pyroxenes have the general formula
1413:
1337:
1279:
706:
228:and pyroxene minerals. Pyroxene and
209:, where they are sometimes found as
154:. Pyroxenes that crystallize in the
24:
1389:(link to youtube: The Lunar Crust)
1338:Brown, Dwayne (October 30, 2012).
162:and those that crystallize in the
25:
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224:of Earth is composed mainly of
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1:
1215:10.1016/j.chemgeo.2016.10.018
1175:
1154:Clinopyroxene thermobarometry
1439:
247:
7:
1307:"Nomenclature of pyroxenes"
1131:
794:(Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)
397:[Mg,Fe,Ca][Mg,Fe]Si
10:
1620:
1282:Introduction to mineralogy
1280:Nesse, William D. (2000).
310:Chemistry and nomenclature
232:are the major minerals in
194:
182:
1563:
1547:
1491:
1480:
1447:
1362:C. Michael Hogan (2010).
1320:: 143–156. Archived from
1255:10.1093/petrology/egn022
1402:Encyclopædia Britannica
880:(Na,Ca,Fe)(Sc,Mg,Fe)Si
762:
746:
720:
512:
485:X-ray diffraction view
410:between pigeonite and
49:(commonly abbreviated
42:
1314:Canadian Mineralogist
752:
726:
714:
648:Coupled substitutions
482:
416:diopside-hedenbergite
370:enstatite-ferrosilite
325:Pyroxene nomenclature
98:(Mg) and more rarely
82:, where X represents
33:
1242:Journal of Petrology
177:is derived from the
166:system are known as
158:system are known as
1574:Minerals portal
1207:2016ChGeo.447....1D
996:(Ca,Mg,Fe)(Mg,Fe)Si
967:(Ca,Na)(Mg,Fe,Al)Si
522:
1555:Industrial mineral
1387:: Lunar Explorers
763:
747:
721:
518:
513:
193:) and 'stranger' (
181:words for 'fire' (
43:
1581:
1580:
1380:Mineral Galleries
980:Ca(Zn,Mn,Mg,Fe)Si
719:of green pyroxene
707:Pyroxene minerals
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211:crystals embedded
16:(Redirected from
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1396:"Pyroxene"
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1327:on 9 March 2008.
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1248:(6): 1187–1221.
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1195:Chemical Geology
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1492:Common minerals
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505:Curiosity rover
493:CheMin analysis
474:aegirine-augite
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408:miscibility gap
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1599:Pyroxene group
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1374:External links
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1106:Nchwaningite,
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1093:Donpeacorite,
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891:Johannsenite,
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844:
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838:CaFe[AlSiO
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806:Clinoenstatite
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374:[Mg,Fe]SiO
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215:volcanic glass
168:orthopyroxenes
160:clinopyroxenes
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60:found in many
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2:
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1604:Metasilicates
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1385:Video Section
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428: CaFeSi
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18:Clinopyroxene
1594:Inosilicates
1565:
1528:
1400:
1384:
1364:
1347:. Retrieved
1333:
1322:the original
1317:
1313:
1300:
1281:
1245:
1241:
1231:
1198:
1194:
1184:
1170:Wollastonite
1027:orthorhombic
847:Hedenbergite
753:A sample of
717:thin section
702:
690:
665:
642:
638:
591:
544:
526:
519:
514:
489:Martian soil
458:
439:wollastonite
385:orthorhombic
356:
313:
258:
251:
222:upper mantle
219:
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174:
172:
167:
164:orthorhombic
159:
94:(Fe(II)) or
50:
46:
44:
1524:Plagioclase
1504:Bridgmanite
1349:October 31,
1074:Ferrosilite
1059:Hypersthene
949:Natalyite,
909:Mn(Mg,Mn)Si
878:Jervisite,
867:Na(Al,Fe)Si
757:(meteorite
381:hypersthene
254:pyroxenoids
66:metamorphic
55:inosilicate
40:Afghanistan
1588:Categories
1509:K-feldspar
1467:Mineralogy
1176:References
1095:(MgMn)MgSi
1063:(Mg,Fe)SiO
921:Kosmochlor
768:monoclinic
755:pyroxenite
732:peridotite
503:and more (
389:monoclinic
156:monoclinic
152:tetrahedra
148:amphiboles
34:Pyroxene (
1499:Amphibole
1264:1460-2415
1223:0009-2541
1165:Rhodonite
1033:Enstatite
1008:Spodumene
992:Pigeonite
963:Omphacite
834:Esseneite
694:CaAlAlSiO
470:omphacite
393:pigeonite
248:Structure
173:The name
144:feldspars
128:manganese
120:magnesium
116:aluminium
104:manganese
96:magnesium
73:XY(Si,Al)
47:pyroxenes
1529:Pyroxene
1448:Overview
1441:Minerals
1201:: 1–10.
1132:See also
1120:·(H
1053:Bronzite
1012:LiAl(SiO
818:Diopside
774:Aegirine
759:ALH84001
735:xenolith
509:Rocknest
497:feldspar
495:reveals
466:aegirine
372:series (
266:cleavage
238:andesite
230:feldspar
175:pyroxene
140:vanadium
136:titanium
132:scandium
112:chromium
58:minerals
36:diopside
1548:Related
1519:Olivine
1472:History
1455:Mineral
1365:Calcium
1203:Bibcode
1159:Emerald
905:Kanoite
863:Jadeite
739:olivine
652:(NaAlSi
501:olivine
462:jadeite
316:cations
262:I-beams
244:rocks.
226:olivine
108:lithium
84:calcium
62:igneous
1539:Spinel
1534:Quartz
1288:
1262:
1221:
938:NaMnSi
925:NaCrSi
893:CaMnSi
851:CaFeSi
822:CaMgSi
790:Augite
778:NaFeSi
743:spinel
728:Mantle
483:First
420:CaMgSi
412:augite
242:gabbro
240:, and
234:basalt
138:(Ti),
134:(Sc),
130:(Mn),
126:(Co),
124:cobalt
122:(Mg),
118:(Al),
114:(Cr),
90:(Na),
88:sodium
86:(Ca),
1325:(PDF)
1310:(PDF)
951:NaVSi
810:MgSiO
691:e.g.,
666:e.g.,
207:lavas
202:xénos
196:ξένος
69:rocks
1514:Mica
1460:List
1351:2012
1344:NASA
1286:ISBN
1260:ISSN
1219:ISSN
1116:(OH)
669:NaFe
507:at "
472:and
464:and
220:The
146:and
100:zinc
92:iron
64:and
45:The
1250:doi
1211:doi
1199:447
1112:SiO
675:0.5
671:0.5
633:Na
630:Ca
627:Li
624:Mn
621:Fe
618:Mg
586:Mn
583:Fe
580:Mg
577:Zn
574:Sc
571:Zr
568:Ti
562:Cr
559:Ti
556:Fe
553:Al
539:Fe
536:Al
533:Si
487:of
359:XYT
213:in
190:pur
184:πυρ
106:or
1590::
1399:.
1342:.
1318:27
1316:.
1312:.
1272:^
1258:.
1246:49
1244:.
1240:.
1217:.
1209:.
1197:.
1193:.
1124:O)
1108:Mn
1082:Si
1078:Fe
1076:,
1061:,
1041:Si
1037:Mg
1035:,
1029:)
1010:,
994:,
965:,
923:,
907:,
865:,
849:,
836:,
820:,
808:,
792:,
776:,
770:)
715:A
677:Si
673:Ti
565:V
511:")
491:–
447:Si
443:Ca
268:.
236:,
199:,
187:,
170:.
102:,
51:Px
1433:e
1426:t
1419:v
1353:.
1294:.
1266:.
1252::
1225:.
1213::
1205::
1122:2
1118:2
1114:3
1110:2
1101:6
1099:O
1097:2
1088:6
1086:O
1084:2
1080:2
1065:3
1047:6
1045:O
1043:2
1039:2
1018:2
1016:)
1014:3
1002:6
1000:O
998:2
986:6
984:O
982:2
973:6
971:O
969:2
957:6
955:O
953:2
944:6
942:O
940:2
931:6
929:O
927:2
915:6
913:O
911:2
899:6
897:O
895:2
886:6
884:O
882:2
873:6
871:O
869:2
857:6
855:O
853:2
842:]
840:6
828:6
826:O
824:2
812:3
800:6
798:O
796:2
784:6
782:O
780:2
730:-
699:.
696:6
686:.
683:6
681:O
679:2
658:6
656:O
654:2
592:X
545:Y
527:T
453:6
451:O
449:2
445:2
434:6
432:O
430:2
426:6
424:O
422:2
418:(
403:6
401:O
399:2
395:(
376:3
365:6
363:O
361:2
79:6
77:O
75:2
20:)
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