404:
26:
432:
series. Intermediate members of this series, high albite, anorthoclase and high sodium sanidine are stable at temperatures of 600 °C (1,100 °F) and above. Below 400–600 °C (800–1,100 °F) only very limited solution exists (less than about 5% on both the low albite and
384:
series, in which the sodium-aluminium silicate member exists in larger proportion. It typically consists of between 10 and 36 percent of KAlSi
571:
694:
662:
38:, Japan. Size: 1.3 cm × 0.9 cm × 0.7 cm (0.5 in × 0.4 in × 0.3 in)
90:
240:
488:. The name is from the Greek αν-, ορθός and κλάσις (not cleaving at right-angles), for its oblique cleavage.
273:
689:
437:
ends). Anorthoclase and high albite exhibit triclinic symmetry, whereas sanidine and the low temperature
445:
symmetry. If the high temperature intermediate composition alkali feldspars are allowed to cool slowly,
80:
469:(shallow intrusive) rocks. The mineral is typically found as a constituent of the fine grained
149:
230:
220:
578:
530:
8:
263:
253:
534:
548:
477:
210:
684:
658:
552:
538:
481:
470:
301:
283:
200:
59:
381:
619:
497:
473:
or as small phenocrysts which may occur as loose crystals in a weathered rock.
429:
377:
125:
100:
678:
333:
190:
112:
408:
31:
134:
543:
518:
466:
446:
442:
438:
434:
403:
605:
105:
25:
462:
450:
425:
346:
52:
637:. Rock Forming Minerals. Vol. 4. Wiley. pp. 2–5, Fig. 1.
485:
421:
35:
195:
Short prismatic crystals; tabular, rhombic, flattened along
185:
Colorless, also white, pale creamy yellow, red, green
476:
It was first described in 1885 for an occurrence on
461:
Anorthoclase occurs in high temperature sodium rich
420:Anorthoclase is an intermediate member of the high
205:Polysynthetic twinning produces a grid pattern on
676:
632:
30:Doubly terminated anorthoclase crystal from
653:Klein, Cornelis; Hurlbut, Cornelius S. Jr.
415:
24:
542:
652:
600:
598:
402:
657:. Wiley. pp. 446–449, Fig. 11-95.
648:
646:
644:
392:and between 64 and 90 percent of NaAlSi
677:
612:
595:
566:
564:
562:
258:Vitreous to pearly on cleavage planes
641:
519:"IMA–CNMNC approved mineral symbols"
516:
13:
559:
14:
706:
626:
510:
1:
503:
456:
407:An anorthoclase crystal from
7:
491:
215:Perfect on , other partings
10:
711:
695:Minerals in space group 2
355:
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300:
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168:β = 116.26°, γ = 90.15°;
166:= 7.15 ; α = 91.05°
148:
133:
111:
99:
89:
79:
58:
48:
43:
23:
18:
572:"Handbook of Mineralogy"
633:Deere; Howie; Zussman.
416:Structure and stability
655:Handbook of Mineralogy
523:Mineralogical Magazine
412:
406:
91:Strunz classification
635:Framework Silicates
544:10.1180/mgm.2021.43
535:2021MinM...85..291W
517:Warr, L.N. (2021).
453:structure results.
376:) is a crystalline
690:Triclinic minerals
478:Pantelleria Island
413:
293:Optical properties
620:"Webmineral data"
362:
361:
351:Measured: 34°–60°
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583:
577:. Archived from
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568:
557:
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546:
514:
482:Trapani Province
428:alkali feldspar
302:Refractive index
284:Specific gravity
245:
144:
123:
120:
65:
64:(repeating unit)
28:
16:
15:
710:
709:
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494:
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387:
382:alkali feldspar
375:
371:
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311:
243:
167:
162:
142:
122:
118:
75:
71:
63:
62:
39:
12:
11:
5:
708:
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671:
670:
663:
640:
625:
611:
594:
558:
529:(3): 291–320.
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501:
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498:Erebus crystal
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490:
458:
455:
430:solid solution
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378:solid solution
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179:
178:
177:Identification
174:
173:
172: = 4
152:
146:
145:
137:
131:
130:
115:
109:
108:
103:
101:Crystal system
97:
96:
93:
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50:
46:
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29:
21:
20:
9:
6:
4:
3:
2:
707:
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664:0-471-80580-7
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584:on 2016-03-04
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454:
452:
449:occurs and a
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427:
423:
410:
405:
401:
383:
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367:
358:
354:
350:
348:
344:
340:
337:
335:
334:Birefringence
331:
328:= 1.527–1.536
324:
320:= 1.524–1.534
316:
312:= 1.519–1.529
308:
305:
303:
299:
295:
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191:Crystal habit
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171:
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160:
156:
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147:
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116:
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113:Crystal class
110:
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67:
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27:
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654:
634:
628:
614:
606:"Mindat.org"
586:. Retrieved
579:the original
526:
522:
512:
475:
460:
419:
411:, Antarctica
409:Mount Erebus
366:anorthoclase
365:
364:The mineral
363:
338:
322:
314:
306:
169:
163:
158:
154:
139:
117:Pinacoidal (
32:Kinki Region
19:Anorthoclase
368:((Na,K)AlSi
296:Biaxial (−)
278:Transparent
274:Diaphaneity
135:Space group
679:Categories
588:2011-12-04
504:References
467:hypabyssal
457:Occurrence
447:exsolution
443:monoclinic
439:orthoclase
435:microcline
356:References
241:Mohs scale
126:H–M symbol
81:IMA symbol
68:(Na,K)AlSi
553:235729616
288:2.57–2.60
150:Unit cell
106:Triclinic
685:Feldspar
492:See also
463:volcanic
451:perthite
426:sanidine
347:2V angle
244:hardness
231:Tenacity
221:Fracture
211:Cleavage
201:Twinning
161:= 12.97
157:= 8.28,
53:Feldspar
49:Category
531:Bibcode
380:in the
341:= 0.008
235:Brittle
95:9.FA.30
60:Formula
44:General
661:
551:
486:Sicily
471:matrix
422:albite
264:Streak
254:Luster
225:Uneven
124:(same
36:Honshu
582:(PDF)
575:(PDF)
549:S2CID
441:have
268:White
182:Color
659:ISBN
465:and
539:doi
85:Ano
681::
643:^
597:^
561:^
547:.
537:.
527:85
525:.
521:.
484:,
480:,
424:–
400:.
121:)
34:,
667:.
622:.
608:.
591:.
555:.
541::
533::
398:8
396:O
394:3
390:8
388:O
386:3
374:8
372:O
370:3
339:δ
326:γ
323:n
318:β
315:n
310:α
307:n
248:6
170:Z
164:c
159:b
155:a
143:1
140:C
128:)
119:1
74:8
72:O
70:3
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