26:
307:. They were described in 1977 by Burham and Veblen. They attracted great mineralogical attention because they were the first examples of new chain silicate structures among a large group known as biopyriboles whose name is derived from the words
346:
The cleavages of jimthompsonite are at 142 degrees and 38 degrees, and 135 degrees and 45 for chesterite; compared to the cleavage angles of pyroxene at about 94 degrees and 86 degrees and amphibole about 124 and 56 degrees.
342:
in sprays up to 5 cm long. They are all colorless to pale pinkish-brown and transparent. As for pyroxene and amphiboles, the type of chain structure dictates the angle between the two distinctive cleavages.
322:
James B. Thompson, Jr. postulated the existence of the new biopyroles in 1970. The theory proved correct when jimthompsonite, clinojimthompsonite and chesterite were discovered in the
Carlton Quarry in
581:
Hiromi
Konishi; Huifang Xu; Dymek, R. F. (2010). "High Resolution Tem study of Jimthompsinite and Chesterite and chain-width disorder in Archean ultramafic rocks from Isua, West Greenland".
692:
92:
687:
666:
186:
623:
Veblen, D. R.; Buseck, P. R.; Burnham, C. W. (1977). "Asbestiform Chain
Silicates: New Minerals and Structural Groups".
416:: Pbca. It has a perfect cleavage, its colorless to pink brown with a density of 3.03 g/cm and hardness of 2–2.5
460:
436:
324:
82:
682:
448:
592:
Thompson, J. B., Jr (1970). "Geometrical possibilities for amphibole structures: model
Biopyriboles".
632:
493:
511:
456:
176:
612:
Veblen, D. R.; Buseck, P. R. (1980). "Microstructures and reaction mechanisms in biopyriboles".
648:
528:
141:
640:
501:
277:
217:
199:
51:
571:
Clements, R.; Robinson D. (1996). "The
Carlton quarry, Chester, Windsor, County, Vermont".
636:
497:
405:
102:
676:
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239:
166:
114:
25:
402:
107:
44:
556:
644:
452:
413:
300:
129:
409:
304:
121:
374:. Veblen and Durham determined the percentages of jimthompsonite as follows:
316:
271:
652:
440:
312:
249:
506:
481:
444:
401:
Some of the other characteristics of jimthompsonite are that it has an
328:
308:
542:
447:
being the most dominant element in its composition. It was named for
432:
417:
602:
Thompson, J. B., Jr. (1978). "Biopyriboles and polysomatic series".
429:
274:
334:
The new minerals are found intergrown with the amphiboles
181:
Perfect on {210} with 38° and 142° intersecting angle
258:
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185:
175:
165:
157:
152:
140:
128:
113:
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91:
81:
50:
40:
35:
18:
420:. It has a white streak and silky-pearly luster.
443:comes from a wide complex chain structure as
8:
355:The chemical formula of jimthompsonite is
24:
505:
171:Radiating sprays and fibrous intergrowths
552:
550:
538:
536:
370:
366:
362:
358:
295:
291:
287:
283:
74:
70:
66:
62:
472:
15:
303:) along with clinojimthompsonite and
299:. It is a triple chain silicate (or
161:Colorless to very light pinkish brown
7:
482:"IMA–CNMNC approved mineral symbols"
14:
148:c = 5.297 ; Z = 8
378:Magnesium 14.71% Mg 24.40% MgO
1:
645:10.1126/science.198.4315.359
449:James Burleigh Thompson, Jr.
439:, US. The name triple chain
428:It is found in the Carleton
384:Silicon 27.20% Si 58.20% SiO
669:in Geology Word of the Week
709:
693:Minerals in space group 61
381:Iron 11.27% Fe 14.50% FeO
23:
461:Cambridge, Massachusetts
390:Hydrogen 0.33% H 2.91% H
30:Jimthompsonite structure
667:J is for Jimthompsonite
437:Windsor County, Vermont
529:Handbook of Mineralogy
486:Mineralogical Magazine
280:with chemical formula
146:a = 18.626, b = 27.23
688:Orthorhombic minerals
614:American Mineralogist
604:American Mineralogist
594:American Mineralogist
583:American Mineralogist
93:Strunz classification
573:Rocks & Minerals
637:1977Sci...198..359V
507:10.1180/mgm.2021.43
498:2021MinM...85..291W
480:Warr, L.N. (2021).
457:Harvard University
412:(2/m 2/m 2/m) and
209:Optical properties
119:Dipyramidal (mmm)
631:(4315): 359–365.
408:dipyramidal with
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264:
204:3.02 (calculated)
700:
656:
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545:
540:
531:
526:
520:
519:
509:
477:
435:, near Chester,
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278:silicate mineral
218:Refractive index
200:Specific gravity
191:
77:
57:
56:(repeating unit)
28:
16:
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568:
566:Further reading
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557:Webmineral data
555:
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541:
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397:Oxygen 46.49% O
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124:: (2/m 2/m 2/m)
120:
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60:
55:
54:
31:
12:
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5:
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661:External links
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492:(3): 291–320.
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406:crystal system
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379:
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325:Windsor County
268:Jimthompsonite
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153:Identification
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103:Crystal system
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19:Jimthompsonite
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705:
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451:(1921–2011),
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340:cummingtonite
337:
336:anthophyllite
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310:
306:
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279:
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240:Birefringence
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167:Crystal habit
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115:Crystal class
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59:
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683:Inosilicates
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606:
603:
596:
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403:orthorhombic
400:
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321:
267:
266:
254:62° measured
134:
108:Orthorhombic
45:Inosilicates
453:petrologist
414:space group
351:Composition
301:inosilicate
212:Biaxial (−)
130:Space group
677:Categories
543:Mindat.org
467:References
410:H-M symbol
317:amphiboles
305:chesterite
259:References
187:Mohs scale
122:H-M symbol
83:IMA symbol
619::599–623.
516:235729616
331:in 1977.
272:magnesium
244:δ = 0.028
230:= 1.626 n
226:= 1.605 n
142:Unit cell
653:17809428
609::239–49.
578::231–35.
441:silicate
313:pyroxene
250:2V angle
190:hardness
177:Cleavage
41:Category
633:Bibcode
625:Science
599::292–93
589::73–80.
494:Bibcode
445:silicon
357:(Mg,Fe)
329:Vermont
309:biotite
282:(Mg,Fe)
234:= 1.633
97:9.DF.05
61:(Mg,Fe)
52:Formula
36:General
651:
514:
463:, US.
433:quarry
424:Origin
418:gypsum
315:, and
512:S2CID
270:is a
194:2–2.5
158:Color
649:PMID
430:talc
369:(OH)
338:and
294:(OH)
275:iron
135:Pbca
73:(OH)
641:doi
629:198
502:doi
455:of
87:Jim
679::
647:.
639:.
627:.
617:65
607:63
597:55
587:95
585:;
576:71
549:^
535:^
510:.
500:.
490:85
488:.
484:.
459:,
367:16
361:Si
327:,
319:.
311:,
292:16
286:Si
71:16
65:Si
655:.
643::
635::
518:.
504::
496::
394:O
392:2
386:2
371:2
365:O
363:6
359:5
296:2
290:O
288:6
284:5
232:γ
228:β
224:α
222:n
75:2
69:O
67:6
63:5
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