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or fibrous to earthy aggregates and crusty coatings from dull yellow to brownish yellow or amber yellow in color. It can be transparent to opaque. It can form from hematite in oxalic acid.
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544:
477:"Formation of Humboldtine During the Dissolution of Hematite in Oxalic Acid – Density Functional Theory (DFT) Calculations and Experimental Verification"
282:
The mineral was already known and characterized when the IMA was founded (1959). Accordingly, humboldtine is listed as an officially recognized mineral.
240:, but only rarely develops well-formed, tabular to prismatic crystals with a resin-like sheen on the surfaces. It is mostly found in the form of
575:"Iron(II)oxalate Dihydrate—Humboldtine: Synthesis, Spectroscopic and Structural Properties of a Versatile Precursor for High Pressure Research"
304:, a 75 year old letter from a coal mine owner written in 1949 was found. It mentioned that mineral was found in coal mine near the town of
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272:
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de Rivero, Mariano (1821). "Note sur une combinaison de l'acide oxalique avec le fer trouvé à Kolowserux, près Belin en Bohéme".
308:. Analysis of the mineral was done which confirmed the discovery. The discovery doubled the amount of Humboldtine known so far.
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It is an important synthetic intermediate and also a key building block for the preparation of various advanced materials.
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Vehmaanperä, Paula; Gong, Bo; Sit, Patrick H.-L.; Barbiellini, Bernardo; Salmimies, Riina; Häkkinen, Antti (2021).
415:"Thermal decomposition of humboldtine –a high resolution thermogravimetric and hot stage Raman spectroscopic study"
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The mineral is known to be found in 30 localities, including
Germany, Brazil, the U.K. and Canada.
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of 1.5 to 2, humboldtine is one of the softest minerals and can be scratched with a fingernail.
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545:"One Of Earth's Rarest Minerals Found Thanks To A 75-Year-Old Letter"
339:= 9.920 Å and β = 128.53°, with four formula units per unit cell.
275:(1798-1857), who named the mineral after the German naturalist
271:
in Okres Most in the Czech
Republic and described in 1821 by
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Müller, Harald; Bourcet, Léa; Hanfland, Michael (2021).
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In 2023, during the digitization of the archive of the
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327:(space group no. 15) with the lattice parameters
316:Humboldtine crystallizes monoclinically in the
115:Perfect on {110}, imperfect on {100} and {010}
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225:O and is therefore a water-containing
18:
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456:from the original on 20 October 2023
413:Frost, R.L.; Weier, Matt L. (2004).
366:"IMA–CNMNC approved mineral symbols"
259:Humboldtine was first discovered by
273:Mariano Eduardo de Rivero y Ustariz
213:" with the chemical composition FeC
14:
295:Bavarian Environment Agency (LfU)
267:deposit near the municipality of
526:Annales de Chimie et de Physique
236:Humboldtine crystallizes in the
27:
555:from the original on 2024-01-29
427:from the original on 2023-11-17
1:
209:from the mineral class of "
662:
646:Minerals described in 1821
502:10.1007/s42860-021-00146-5
238:monoclinic crystal system
26:
481:Clays and Clay Minerals
170:2.307 g/cm (calculated)
370:Mineralogical Magazine
277:Alexander von Humboldt
205:is a rarely occurring
105:Yellow to amber-yellow
255:Etymology and history
158:Transparent to opaque
229:or the iron salt of
168:2.28 g/cm (measured)
631:Monoclinic minerals
600:10.3390/min11020113
591:2021Mine...11..113M
493:2021CCM....69..655V
391:10.1180/mgm.2021.43
382:2021MinM...85..291W
364:Warr, L.N. (2021).
641:Iron(II) minerals
312:Crystal structure
261:August Breithaupt
211:organic compounds
200:
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653:
636:Oxalate minerals
626:Organic minerals
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543:Bressan, David.
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227:iron(II) oxalate
176:Refractive index
138:Resinous to dull
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56:(repeating unit)
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16:Oxalate mineral
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487:(6): 655–662.
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97:Identification
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88:Crystal system
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446:"Humboldtine"
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249:Mohs hardness
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557:. Retrieved
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460:15 September
458:. Retrieved
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429:. Retrieved
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331:= 12.011 Å;
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335:= 5.557 Å;
318:space group
298: [
231:oxalic acid
203:Humboldtine
154:Diaphaneity
148:Pale yellow
22:Humboldtine
615:Categories
585:(2): 113.
559:2024-01-29
532:: 207–210.
450:MinDat.org
431:2024-01-29
351:References
306:Schwandorf
286:Occurrence
265:brown coal
242:botryoidal
121:Mohs scale
92:Monoclinic
78:IMA symbol
511:238244314
400:235729616
269:Korozluky
621:Minerals
579:Minerals
553:Archived
454:Archived
422:Archived
128:1.5 to 2
124:hardness
111:Cleavage
41:Category
587:Bibcode
489:Bibcode
378:Bibcode
247:With a
207:mineral
196:= 1.692
190:= 1.561
184:= 1.494
164:Density
52:Formula
45:Mineral
36:General
549:Forbes
509:
398:
144:Streak
134:Luster
507:S2CID
425:(PDF)
418:(PDF)
396:S2CID
302:]
102:Color
462:2021
343:Uses
595:doi
497:doi
386:doi
221:•2H
82:Hbd
68:·2H
60:FeC
617::
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323:2/
300:de
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337:c
333:b
329:a
325:c
321:C
223:2
219:4
217:O
215:2
194:γ
192:n
188:β
186:n
182:α
180:n
72:O
70:2
66:4
64:O
62:2
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