622:) examined microscopically furnish examples of every stage of the process. The chemical changes involved are really small, one of the most important being the assumption of a small amount of chlorine in the new molecule. Often the scapolite is seen spreading through the feldspar, portions being completely replaced, while others are still fresh and unaltered. The feldspar does not weather, but remains fresh, and the transformation resembles metamorphism rather than weathering. It is not a superficial process, but apparently takes place at some depth under pressure, and probably through the operation of solutions or vapours containing chlorides. The basic soda-lime feldspars (
630:) are those that undergo this type of alteration. Many instances of scapolitization have been described from the ophites (diabases) of the Pyrenees. In the unaltered state these are ophitic and consist of pyroxene enclosing lath-shaped plagioclase feldspars; the pyroxene is often changed to uralite. When the feldspar is replaced by scapolite the new mineral is fresh and clear, enclosing often small grains of hornblende. Extensive recrystallization often goes on, and the ultimate product is a spotted rock with white rounded patches of scapolite surrounded by granular aggregates of clear green hornblende: in fact the original structure disappears.
29:
385:
377:
582:). At the contacts scapolite occurs in a great number of places, both in the limestones and in the calcareous shales that accompany them. In some of these rocks large crystals of one of the scapolite minerals (an inch or two in length) occur, usually as octagonal prisms with imperfect terminations. In others the mineral is found in small irregular grains. It is sometimes clear, but often crowded with minute enclosures of
885:
656:, veins rich in tourmaline have been formed, and the surrounding rocks at the same time permeated by that mineral. In the composition of the active gases a striking difference is shown, for those that emanate from the granites are mainly fluorine and boron, while those from the gabbro are principally chlorine and phosphorus. In one case the feldspar is replaced by quartz and white mica (in
521:. Even marialite (the variety richest in soda) occurs in this association, being principally obtained in small crystals lining cavities in ejected blocks of crystalline limestone at Vesuvius and the craters of the Eifel in Germany. Scapolite and wernerite are far more common at the contacts of limestone with intrusive masses. The minerals that accompany them are
664:
rocks); in the other case scapolite is the principal new product. The analogy is a very close one, and this theory receives much support from the fact that in Canada (at various places in Ottawa and
Ontario) there are numerous valuable apatite vein deposits. They lie in basic rocks such as gabbro and
594:
and other minerals, such as constitute the surrounding matrix. From these districts also a black variety is well known, filled with minute graphitic enclosures, often exceedingly small and rendering the mineral nearly opaque. The names couzeranite and dipyre are often given to this kind of scapolite.
642:
and other localities. They have been called spotted gabbros, but usually do not contain feldspar, the white spots being entirely scapolite while the dark matrix enveloping them is an aggregate of green or brownish hornblende. In many features they bear a close resemblance to the scapolitized ophites
647:
solutions along lines of weakness, or planes of solubility, filling cavities etched in the substance of the mineral. Subsequently the chlorides were absorbed, and the feldspar was transformed into scapolite. But it is found that in these gabbros there are veins of a chlorine-bearing apatite, which
677:
In many parts of the world metamorphic rocks of gneissose character occur containing scapolite as an essential constituent. Their origin is often obscure, but it is probable that they are of two kinds. One series is essentially igneous (orthogneisses); usually they contain pale green pyroxene, a
553:
material. They are not in very perfect crystals, though sometimes incomplete octagonal sections are visible; the tetragonal cleavage, strong double refraction and uniaxial interference figure distinguish them readily from other minerals. Commonly they weather to micaceous
425:), and at times of considerable size. They are distinct and usually have the form of square columns, some cleavages parallel to the prism-faces. Crystals are usually white or greyish-white and opaque, though meionite is found as colorless glassy crystals in the ejected
820:
453:, etc., and this is the cause of the usual opacity of the crystals. Owing to this alteration, and to the variations in composition, numerous varieties have been distinguished by special names. Scapolite is commonly a mineral of
643:
of the
Pyrenees. It has been suggested that the conversion of their original feldspar (for there can be no doubt that they were once gabbros, consisting of plagioclase and pyroxene) into scapolite is due to the percolation of
690:, etc. In many of them there is no reason to doubt that the scapolite is a primary mineral. Other scapolite gneisses equally metamorphic in aspect and structure appear to be
570:) that have suffered thermal metamorphism. In the Pyrenees there are extensive outcrops of limestone penetrated by igneous rocks described as ophites (varieties of
562:
they occur in small and usually inconspicuous grains mingled with the other components of the rock. Large, nearly idiomorphic crystals are sometimes found in
706:-schists makes this correlation in every way probable. Biotite is a common mineral in these rocks, which often contain also much quartz and alkali feldspar.
906:
549:. The scapolites are colorless, flesh-colored, grey or greenish; occasionally they are nearly black from the presence of very small enclosures of
897:
441:
varies with the chemical composition between 2.7 (meionite) and 2.5 (marialite). The scapolites are especially liable to alteration by
702:, etc.), which suggests that they were originally impure limestones. The frequent association of this type with graphitic-schists and
517:, it is to be expected that these minerals will be found where impure limestones have been crystallized by contact with an igneous
821:"Silvialite, a new sulfate-dominant member of the scapolite group with an Al-Si composition near the 14/m–P42/n phase transition"
104:
28:
947:
137:
942:
599:
in small quantities, which may often be detected in limestones, to some extent determines the formation of the mineral.
669:, and these in the neighborhood of the veins have been extensively scapolitized, like the spotted gabbros of Norway.
384:
682:, and iron oxides. Quartz, rutile, green hornblende and biotite are often present, while garnet occurs sometimes;
558:, but sometimes an isotropic substance of unknown nature is seen replacing them. In crystalline limestones and
937:
51:
559:
563:
94:
921:
832:
736:
639:
477:
are known as dipyre or couzeranite. Large crystals of common scapolite (wernerite) are found in the
555:
434:
209:
127:
117:
856:
754:
84:
338:
807:
848:
691:
510:
252:
44:
890:
One or more of the preceding sentences incorporates text from a publication now in the
840:
744:
438:
165:
147:
912:
Chisholm, Hugh, ed. (1911). Encyclopædia
Britannica (11th ed.). Cambridge University Press
782:
376:
771:
836:
740:
648:
must have been deposited by gases or fluids ascending from below. This suggests that a
238:
61:
931:
901:
891:
860:
758:
649:
611:
189:
695:
615:
538:
454:
222:
686:
is rare. They occur along with other types of pyroxene gneiss, hornblende gneiss,
473:. The long slender prisms abundant in the crystalline marbles and schists in the
687:
683:
623:
530:
501:
According to their genesis the scapolite rocks fall naturally into four groups.
486:
400:
219:
199:
703:
666:
587:
579:
575:
442:
415:
79:
Pink, red, blue, brown, white, grey, colourless, green, yellow, orange, purple
910:. Vol. 24 (11th ed.). Cambridge University Press. pp. 300–301.
852:
844:
627:
614:, such as gabbro and diabase, scapolite replaces feldspar by a secondary or
546:
426:
422:
411:
408:
388:
314:
283:
275:
256:
819:
Teertstra, D. K.; Schindler, M.; Sherriff, B. L.; Hawthorne, F. C. (1999).
699:
652:
process has been at work, similar to that by which, around intrusions of
644:
596:
550:
542:
474:
462:
430:
404:
392:
287:
271:
267:
749:
724:
878:
876:
874:
872:
870:
796:
657:
653:
619:
591:
571:
526:
522:
514:
478:
418:
279:
260:
679:
661:
583:
534:
490:
482:
470:
466:
458:
450:
264:
694:. Many of them contain calcite or are very rich in calc-silicates (
608:
567:
518:
383:
375:
446:
638:
In Norway scapolite-hornblende rocks have long been known at
481:
deposits in the neighborhood of Bamble near Brevik in
896:
Flett, John Smith; Spencer, Leonard James (1911). "
380:
Fluorescence of an intermediate member of the group
218:
208:
198:
188:
164:
156:
146:
136:
126:
116:
103:
93:
83:
75:
70:
60:
50:
40:
35:
21:
485:, and have resulted from the alteration of the
618:process. Some Norwegian scapolite-gabbros (or
8:
246:
368:is also a recognized member of the group.
748:
457:origin, occurring usually in crystalline
421:are hemihedral with parallel faces (like
395:at the National Museum of Natural History
792:
790:
673:Metamorphic rocks of gneissose character
505:Limestones and contact metamorphic rocks
363:
359:
355:
351:
347:
343:
332:
328:
324:
320:
309:
305:
301:
297:
293:
715:
251:, "stone") are a group of rock-forming
227:Inert to strong pink, orange and yellow
16:Group of rock-forming silicate minerals
18:
509:The scapolite limestones and contact
7:
725:"IMA–CNMNC approved mineral symbols"
445:processes, with the development of
14:
391:, a component of scapolite, from
883:
27:
660:) or quartz and tourmaline (in
1:
808:Silvialite data on Webmineral
797:Scapolite group on Mindat.org
783:Miarialite data on Webmineral
678:variable amount of feldspar,
772:Meionite data on Webmineral
595:Apparently the presence of
99:Conchoidal, uneven, brittle
964:
634:Scapolite-hornblende rocks
247:
242:
26:
907:Encyclopædia Britannica
845:10.1180/002646199548547
513:. As silicates rich in
497:Scapolite bearing rocks
429:blocks of Monte Somma,
825:Mineralogical Magazine
729:Mineralogical Magazine
396:
381:
387:
379:
142:Opaque to transparent
89:Good, in 2 directions
948:Luminescent minerals
566:(altered calcareous
943:Tetragonal minerals
837:1999MinM...63..321T
750:10.1180/mgm.2021.43
741:2021MinM...85..291W
723:Warr, L.N. (2021).
603:Mafic igneous rocks
560:calc–silicate rocks
564:argillaceous rocks
397:
382:
204:Moderate to strong
157:Optical properties
922:Mineral galleries
692:sedimentary rocks
511:metamorphic rocks
253:silicate minerals
231:
230:
955:
913:
911:
889:
887:
886:
880:
865:
864:
816:
810:
805:
799:
794:
785:
780:
774:
769:
763:
762:
752:
720:
461:, but also with
439:specific gravity
437:is 5–6, and the
399:The group is an
367:
336:
312:
250:
249:
244:
166:Refractive index
148:Specific gravity
109:
31:
19:
963:
962:
958:
957:
956:
954:
953:
952:
928:
927:
926:
917:
916:
895:
884:
882:
881:
868:
818:
817:
813:
806:
802:
795:
788:
781:
777:
770:
766:
722:
721:
717:
712:
675:
636:
605:
507:
499:
403:mixture of the
374:
365:
361:
357:
353:
349:
345:
341:
334:
330:
326:
322:
318:
311:
307:
303:
299:
295:
291:
183:
177:
175:
107:
22:Scapolite group
17:
12:
11:
5:
961:
959:
951:
950:
945:
940:
938:Tectosilicates
930:
929:
925:
924:
918:
915:
914:
902:Chisholm, Hugh
866:
831:(3): 321–329.
811:
800:
786:
775:
764:
735:(3): 291–320.
714:
713:
711:
708:
674:
671:
635:
632:
604:
601:
506:
503:
498:
495:
373:
370:
229:
228:
225:
216:
215:
212:
206:
205:
202:
196:
195:
192:
186:
185:
181:
173:
168:
162:
161:
158:
154:
153:
150:
144:
143:
140:
134:
133:
130:
124:
123:
120:
114:
113:
110:
101:
100:
97:
91:
90:
87:
81:
80:
77:
73:
72:
71:Identification
68:
67:
64:
62:Crystal system
58:
57:
54:
48:
47:
45:Tectosilicates
42:
38:
37:
33:
32:
24:
23:
15:
13:
10:
9:
6:
4:
3:
2:
960:
949:
946:
944:
941:
939:
936:
935:
933:
923:
920:
919:
909:
908:
903:
899:
893:
892:public domain
879:
877:
875:
873:
871:
867:
862:
858:
854:
850:
846:
842:
838:
834:
830:
826:
822:
815:
812:
809:
804:
801:
798:
793:
791:
787:
784:
779:
776:
773:
768:
765:
760:
756:
751:
746:
742:
738:
734:
730:
726:
719:
716:
709:
707:
705:
701:
697:
693:
689:
685:
681:
672:
670:
668:
663:
659:
655:
651:
650:pneumatolytic
646:
641:
633:
631:
629:
625:
621:
617:
613:
612:igneous rocks
610:
602:
600:
598:
593:
589:
585:
581:
577:
573:
569:
565:
561:
557:
552:
548:
544:
540:
536:
532:
528:
524:
520:
516:
512:
504:
502:
496:
494:
492:
488:
484:
480:
476:
472:
468:
464:
460:
456:
452:
448:
444:
440:
436:
432:
428:
424:
420:
417:
413:
410:
406:
402:
394:
390:
386:
378:
371:
369:
340:
316:
289:
285:
281:
277:
273:
269:
266:
262:
258:
254:
245:, "rod", and
240:
236:
226:
224:
221:
217:
213:
211:
207:
203:
201:
197:
193:
191:
190:Birefringence
187:
184:= 1.526–1.565
180:
176:= 1.555–1.594
172:
169:
167:
163:
159:
155:
151:
149:
145:
141:
139:
135:
131:
129:
125:
121:
119:
115:
111:
106:
102:
98:
96:
92:
88:
86:
82:
78:
74:
69:
65:
63:
59:
55:
53:
49:
46:
43:
39:
34:
30:
25:
20:
905:
828:
824:
814:
803:
778:
767:
732:
728:
718:
696:wollastonite
688:amphibolites
676:
637:
606:
539:wollastonite
508:
500:
398:
255:composed of
234:
232:
223:fluorescence
178:
170:
160:Uniaxial (–)
684:hypersthene
624:labradorite
616:metasomatic
580:peridotites
576:lherzolites
531:vesuvianite
487:plagioclase
455:metamorphic
401:isomorphous
220:Ultraviolet
200:Pleochroism
194:0.004–0.038
138:Diaphaneity
932:Categories
710:References
704:andalusite
667:pyroxenite
588:tourmaline
443:weathering
416:tetragonal
412:endmembers
372:Properties
339:Silvialite
284:endmembers
282:. The two
235:scapolites
210:Dispersion
105:Mohs scale
66:Tetragonal
52:IMA symbol
898:Scapolite
861:129588463
853:0026-461X
759:235729616
640:Ødegården
628:anorthite
556:aggregate
551:graphitic
547:amphibole
427:limestone
423:scheelite
409:marialite
389:Marialite
315:marialite
276:carbonate
257:aluminium
700:diopside
645:chloride
607:In many
597:chlorine
543:diopside
475:Pyrenees
471:gneisses
463:pyroxene
435:hardness
431:Vesuvius
419:crystals
405:meionite
393:Tanzania
288:meionite
272:chlorine
268:silicate
152:2.6–2.74
122:Vitreous
108:hardness
95:Fracture
85:Cleavage
41:Category
904:(ed.).
894::
833:Bibcode
737:Bibcode
658:greisen
654:granite
620:diorite
592:biotite
572:diabase
527:epidote
523:calcite
515:calcium
479:apatite
467:schists
459:marbles
342:(Ca,Na)
280:sulfate
261:calcium
36:General
900:". In
888:
859:
851:
757:
680:sphene
662:schorl
584:augite
574:) and
568:shales
535:garnet
491:gabbro
483:Norway
451:kaolin
433:. The
414:. The
313:) and
265:sodium
263:, and
243:σκάπος
128:Streak
118:Luster
857:S2CID
755:S2CID
609:mafic
519:magma
489:of a
270:with
248:λίθος
239:Greek
214:0.017
132:White
112:5.5–6
76:Color
849:ISSN
545:and
469:and
447:mica
407:and
286:are
278:and
233:The
841:doi
745:doi
626:to
465:in
362:,CO
358:(SO
337:).
56:Scp
934::
869:^
855:.
847:.
839:.
829:63
827:.
823:.
789:^
753:.
743:.
733:85
731:.
727:.
698:,
590:,
586:,
541:,
537:,
533:,
529:,
525:,
493:.
449:,
356:24
350:Si
346:Al
335:Cl
333:24
327:Si
323:Al
319:Na
308:CO
306:24
300:Si
296:Al
292:Ca
274:,
259:,
241::
863:.
843::
835::
761:.
747::
739::
578:(
366:)
364:3
360:4
354:O
352:6
348:6
344:4
331:O
329:9
325:3
321:4
317:(
310:3
304:O
302:6
298:6
294:4
290:(
237:(
182:ε
179:n
174:ω
171:n
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