587:
29:
611:
380:, to break, because the mineral was thought to have a less perfect cleavage than albite. It had previously been recognized as a distinct species by
658:
478:
where its presence is a defining feature. It also occurs in gneiss. The best developed and largest crystals are those found with orthoclase,
602:
648:
313:
are: nα = 1.533–1.543, nβ = 1.537–1.548, and nγ = 1.542–1.552. In color it is usually white, with shades of grey, green, or red.
173:
370:
350:
704:
397:
694:
689:
684:
420:; this presents a brilliant red to golden metallic glitter, due to the presence of numerous small scales of
384:
in 1824, and was named by him soda-spodumene (Natron-spodumen), because of its resemblance in appearance to
361:
341:
251:. In chemical composition and in its crystallographic and physical characters it is intermediate between
598:
163:
523:
196:
186:
679:
448:
153:
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337:
630:. «Memories of the Stone». — Moscow: Publishing House of the USSR Academy of Sciences, 1958.
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One or more of the preceding sentences incorporates text from a publication now in the
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28:
653:
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527:
499:
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294:). The albite:anorthite molar ratio of oligoclase ranges from 90:10 to 70:30.
131:
546:
475:
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298:
275:
111:
98:
545:
One of the iridescent varieties of oligoclase, discovered in 1925 near the
471:
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80:
51:
615:. Vol. 20 (11th ed.). Cambridge University Press. p. 82.
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Perfectly colorless and transparent glassy material found at
404:. Another variety more frequently used as a gemstone is the
408:-feldspar or sun-stone found as reddish cleavage masses in
375:
355:
297:
Oligoclase is a high sodium feldspar crystallizing in the
526:
and show
Schiller iridescence due to the presence of
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nα = 1.533–1.543; nβ = 1.537–1.548; nγ = 1.542–1.552
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148:Usually white, with shades of grey, green, or red
639:Hurlbut, Cornelius S.; Klein, Cornelis, 1985,
8:
553:, became widely known under the trade name
316:Oligoclase is a common mineral in the more
580:
578:
576:
574:
572:
570:
498:is due to oligoclase rims on orthoclase
424:oriented within the feldspar structure.
16:Sodium-rich plagioclase feldspar mineral
566:
530:lamellae on cooling in the peristerite
494:in Norway. The distinctive texture of
427:Oligoclase occurs, often accompanying
158:Perfect {001}, Good {010}, Poor {110}.
18:
7:
400:has occasionally been faceted as a
14:
336:The name oligoclase was given by
33:Oligoclase from Chihuahua, Mexico
585:
27:
431:, as a constituent of plutonic
502:. Oligoclase is also found in
1:
376:
356:
398:Bakersville, North Carolina
721:
506:formed under transitional
365:
345:
522:Some examples are called
26:
97:, where Ca/(Ca + Na) (%
612:Encyclopædia Britannica
490:in veins in granite at
599:Spencer, Leonard James
168:Uneven, sub-conchoidal
549:coast by academician
309:is 2.64 to 2.66. The
641:Manual of Mineralogy
518:Schiller iridescence
305:is 6 to 6.5 and the
643:, 20th ed., Wiley,
514:facies conditions.
320:-rich varieties of
101:) is between 10–30%
705:Triclinic minerals
462:as well as in the
332:Name and discovery
311:refractive indices
240:is a rock-forming
659:Mineral galleries
627:Alexander Fersman
551:Alexander Fersman
504:metamorphic rocks
374:
354:
340:in 1826 from the
338:August Breithaupt
326:metamorphic rocks
244:belonging to the
235:
234:
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695:Calcium minerals
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496:rapakivi granite
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307:specific gravity
217:Refractive index
207:Specific gravity
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129:
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68:
67:(repeating unit)
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19:
720:
719:
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690:Sodium minerals
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654:Webmineral data
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532:miscibility gap
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447:. It occurs in
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382:J. J. Berzelius
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685:Tectosilicates
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607:Chisholm, Hugh
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360:, little, and
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140:Identification
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109:
107:Crystal system
103:
102:
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649:0-471-80580-7
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594:public domain
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433:igneous rocks
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342:Ancient Greek
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308:
304:
303:Mohs hardness
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230:
228:
227:Birefringence
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119:Crystal class
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57:
56:tectosilicate
53:
49:
46:
42:
37:
30:
25:
20:
640:
625:
621:
610:
544:
521:
426:
416:in southern
395:
335:
324:and in many
322:igneous rock
315:
301:system. The
296:
237:
236:
211:2.64 to 2.66
123:Pinacoidal (
512:amphibolite
508:greenschist
500:phenocrysts
414:Tvedestrand
246:plagioclase
48:plagioclase
674:Categories
603:Oligoclase
561:References
555:belomorite
528:exsolution
429:orthoclase
406:aventurine
392:Occurrence
238:Oligoclase
174:Mohs scale
132:H-M symbol
22:Oligoclase
680:Gemstones
601:(1911). "
547:White Sea
524:moonstone
476:mugearite
474:, and in
386:spodumene
371:romanized
351:romanized
299:triclinic
276:anorthite
249:feldspars
231:1st order
112:Triclinic
99:anorthite
700:Feldspar
472:trachyte
468:andesite
464:volcanic
449:porphyry
435:such as
422:hematite
402:gemstone
191:Vitreous
181:6 to 6.5
177:hardness
164:Fracture
154:Cleavage
52:feldspar
44:Category
609:(ed.).
596::
492:Arendal
488:calcite
484:epidote
466:rocks
453:diabase
445:diorite
441:syenite
437:granite
373::
353::
242:mineral
63:Formula
39:General
664:Mindat
647:
605:". In
590:
486:, and
480:quartz
443:, and
418:Norway
410:gneiss
357:oligos
346:όλίγος
318:silica
274:) and
253:albite
197:Streak
187:Luster
130:(same
534:, ~An
460:sills
456:dikes
201:White
145:Color
645:ISBN
470:and
458:and
451:and
377:klân
366:κλᾶν
538:-An
510:to
412:at
54:,
676::
569:^
557:.
542:.
540:18
482:,
439:,
388:.
368:,
364::
348:,
344::
328:.
286:Si
282:Al
280:Ca
263:Si
260:Al
257:Na
127:)
85:Si
81:Al
79:)(
77:Na
73:Ca
50:,
536:5
292:8
290:O
288:2
284:2
278:(
272:8
269:O
266:3
255:(
134:)
125:1
95:8
92:O
89:4
87:)
83:,
75:,
71:(
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