MINERALS OF THE WORLD: SYSTEMATICS AND GEOLOGY..

 

Minerals of the World: their Etymologies, Origins and Ideal Chemical Compositions

By: PhD Dr. Paulo César Pereira das Neves (usppd@yahoo.com.br).

(This work is exclusively scientific dissemination and has no commercial value).

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One of the most enigmatic phrases I've ever heard, was in a Mineralogy class, uttered by the late Prof. Dr. Jorge Alberto Willwock - "minerals represent the flowers of the inanimate world". And, if we think about it, they are, because the colors, the shine, the shapes, honestly, take us back to the plant world, to Nature in its most beautiful splendor. They are irreproducible entities, ne minerals is never the same as another:

A mineralogical species is a natural solid formed by geological processes. These must be, therefore, the relevant factors in the determination of a mineral and in the proposition of new species, whether on Earth or in extra-terrestrial bodies, with well-defined chemical composition and crystallographic properties, these being the key factors for the definition of a new mineral species is justified (NICKEL; GRICE, 1998 in ATENCIO, 2020).

By crystalline structure, we mean internal ordering, on the atomic scale, where atoms are arranged in a regular geometric pattern. The constituent atoms of a mineral are distributed in an orderly manner, forming a network called crystal lattice. This network is formed by fundamental atomic or ionic units, which are repeated three-dimensionally, being called the united cell of the mineral (which serves as the basis for the formation of the crystalline crystalline reticulum), where each atom occupies a well-defined position in space. The internal arrangement is an important feature of the solid state. Special cases of non crystalline substances are those that are liquid under ambiental conditions. Water in liquid form is not considered a mineral, but in solid form, such as ice (H₂O) found in the polar ice caps or in caves in regions with a very cold climate. Ice is considered a mineral, because when water molecules freeze they assume an ordered arrangement, characteristic of the crystalline solid state. Mercury (Hg) is recognized as a mineral even through it does not occur in a solid state under Earth's environmental conditions (the only exception). This substance only acquired an internal crystalline structure (hexagonal system) from -39,5°C.

The vast majority of minerals crystallize in a single crystalline system. Only a few substances, including analcime (NaAlSi₂O₆.2H₂O), can crystallize in different systems, in the case of cubic, tetragonal, trigonal, orthorhombic, monoclinic and triclinic.

The term naturally, used in the definition of mineral, indicates that only substances formed spontaneously in nature, by some geological process, are considered minerals.

Spodumene crystals (colorless) - "kunzite" (green) and "hiddenite " (pink) varieties -Araçuai, Galileia, Minas Gerais, Brazil (Source: Mineral collection of UBRA; photo: Luciano Valério).

A mineral must be formed, generally, by inorganic process, that is, originating from geological processes. Howerer, some biogenic substances, produced by biological processes at the source, included in the definition of mineral, provided that they respect the other pre-established conditions. Examples of these substances are the shells of mollusks and coral reefs (composed of aragonite and vaterite (CaCO₃) and monohydrocalcite (CaCO₃.H₂O); kidney stones (formed by apatite-CaF (Ca₅(PO₄)₃F), apatite-CaOH (Ca₅(PO₄)₃OH) and whitlockite (Ca₉Mg)PO₃OH)PO₆, among others. Such substances, despite being generated by organisms, have inorganic chemical compounds identical to the natural forms of minerals.

Fossil coal and oil, although formed by geological processes, are not considered minerals, as they do not have a specific chemical composition or ordered atomic arrangement. In addition to the fact that, in their origin, they are formed by organic carbon, found in biological materials. Howerer, in some cases, if some geological processes acts of the organic matter, the product can be accepted as a mineral. Examples of validated minerals of this type are substances crystallized from organic matter, in black shales. such as abelsonite C₃₁H₃₂N₄Ni (NEVES et al., 2015) and limestone constituents derived from marine organisms.

Every year, between 40-50 new mineralogical species are discovered for science. Others, an almost insignificant numbers, are discredited by the International Mineralogical Association (IMA), the body that regulates and standardizes these substances at global level. Many others still undergo changes in their nomenclatural base. All of this is due to the new modern analytical techniques that chemistry makes available to us, stimulating and enabling scientists to work with substances of very reduced sizes, which until recently was something unthinkable to do. Also, with he space race, promoted by man, and with the exploration of substrates at the bottom of the oceans, rocks containing minerals hitherto unknown on Earth have been investigated. Currently, 6,126 species are known (IMA MASTER LIST - March, 2025). The minerals are classified into seven crystalline system mentioned above. Each of these systems serves as the basis for the 14 spatial configurations, which represent the crystalline reticules established by Augusto Bravais, in 1848, which ended up generating the 230 spatial groups of crystalline substances. The fundamental form of each system represents the spatial configuration of the unit cell of the substances that crystallize in it.

The objective of this work is to demonstrate, in a complete and up-to-date manner, the mineral world from a historical and cultural of view, based mainly on the Updated list of IMA-approved mineral (March 2025) - (although the subject is by its nature a work in progress). The images were mostly taken from google.images, Mindat.org., RRUFF Project.

The systematic classification is based on NICKEL; STRUNZ, 2002 and annexes. Bellow, in alphabetical order, are described the mineral species described the mineral species existing on Earth, on the Moon and some planets of the Solar System, in addition to those that occur in meteorites, which are considered to belong to the place where the respective bolides crash sites. After the name of each mineral species its symbol is placed, suggested by WARR (2021) and made official by the IMA. Images of crystalline structures follow the American Mineralogical Crystal Structure Database and X-ray diagrams were taken from the RRUFF Project, University of Arizona, with permission from Dr. Robert Downs.

All images used go with their respective credits. Eventually, in some cases we were unable to contact them authorization. If someone does not agree with their publication, please contact us (usppd@yahoo.com.br), and we will immediately remove them from the blogger.

To all those consultants, mineralogists, mineral collectors or those interested in the subject, we wish a good reading. Any errors detected, we request assistance to that they are property corrected.

Reference(s):

ATENCIO, D. Type Mineralogy of Brazil a book in progress. Instituto de Geociências USP: São Paulo, 2020, 662 pp.

IMA – The official IMA-CNMNC List of Mineral Names – Updated list of IMA approved minerals (March, 2025) http://cnmnc.main.jp/IMA_Master_List_%282022-11%29.pdf.

NEVES, P. C. P. das; CORRÊA, D. S.; CARDOSO, J. C. A classe mineralógica das combinações orgânicas associadas ao hidrogênio. Terra e Didatica, v. 4, n. 1, pp. 51-66, 2015.

NICKEL, E. H.; STRUNZ, K. H. Strunz Mineralogical Tables – Chemical Structural Mineral Classification System, Schweizerbart’sche Verlagsbuchhandlung: Sttutgart, 9^th ed. 2002, 870 pp. (2010 – 10^thed. – pending). 

WARR, L. N. IMA-CNMNC approved mineral symbols. The Mineralogical Magazine, v. 85, n. 3, pp 291-320, 2021.

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Next, we will make a brief description of each existing mineralogical species, sorting them in alphabetical order.

1.  ABELLAITE (Abe) - NaPb₂(CO₃)₂(OH)

Chemical data and Nickel-Strunz classes: molecular mass = 574.42 gmol 1^-; elemental contents: Pb = 72.14%, O = 19.50%, C = 4.18%, Na = 4.00%, H = 0.18%; oxide contents: PbO = 77.72%, CO₂ = 15.32%, Na₂O 5.39%, H₂O = 1.57%.               Carbonates - 5.BE.X.

b) IMA status: validated species (2014). 

Type-locality(ies): 

Eureka mine, Castell-estaó, La Torre de Cabdella (Capdella), La Vall Fosca, El Pallars Jussà, Lleida, Catalonia, Spain.

Repository(ies) (type-material): Natural History Museum, Barcelona, Spain (catalog(s): MGB 26,350).

Name origin: 

in honor to Catalan gemologist, Dr. Joan Abella i Creus (☼1968), from Sabadel, Spain, who researched the mineral resources of the Eureka mine, where she first found this species (You Tube).

Images:

Abellaite (mineral collection and photography: Stephan Wolfsried, Wiblingen, Germany).

Crystal system: hexagonal and crystalline structure (RRUFF Project).

D  Genesis: secondary mineral that forms sparse coatings from supergene enrichment of a red-bad, sediment-hosted U-V-Cu deposit, may be associated with andersonite Na₂Ca(UO₂)(CO₃)₃.6H₂O, calcite CaCO₃, dolomite CaMg(CO₃)₂,  galena PbS,  natrolite Na₂Al₂Si₃O₁₀.2H₂O, sanrománite Na₂Ca 

 P  Pb₃(CO₃)₅, scolecite CaAl₂Si₃O₁₀.3H₂O,  and seidite-(Ce) Na₂

  (Ce,Sr)₂[TiSi₈O₁₈(O,OH)₂](O,OH,F)₄.5H₂O. (IBAÑEZ-INSA et al., 2017).

OOccurrence(s): Russia and Spain (for more details, see Mindat.org in the page of mineral).

Reference(s):

IBÁÑEZ-INSA, J.; ELVIRA, L. X.; PÉREZ-CANO, J.; ORIOLS, N.; BUSQUETS-MASÓ, M.; HERNÁNDEZ, S. Abellaite, NaPb₂(CO₃)₂(OH), a new supergene mineral from the Eureka mine, Lleida Province, Catalonia, Spain. European Journal of Mineralogy, v. 29, n. 5, pp. 915-922, 2017.

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2.  ABELSONITE (Abl) - C₃₁H₃₂N₄Ni

Chemical data and Nickel-Strunz classes: molecular mass = 519.31 gmol^1-; elemental contents: C = 71.70%, Ni = 11.31%, C = 4.18%, N = 10.79%, H = 6.21%.

Organic Compounds - 10.CA.20.

b) IMA status: validated species (1975). 

Type-locality(ies):

Big Pack Mountains, Green River Formation, Wosco well, Uintah Co., Utah, United States of America.

Repository(ies) (type-material): Natural History Museum, London, England (catalog(s): 1979-136); National Museum of Natural History, Washington, D. C., United States of America (catalog(s): 143,566; 145,712).  

Name origin:  

in honor to American physicist, Prof. Dr. Philip Hauge Abelson (☼ Tacoma, 1913 - ┼ Bethesda, 2004), co-responsible for the discovery to the chemical element neptunium (Z = 93), editor of the journal Science (1962-1984), director of the Carnegie Institution and its Geophysical Laboratory (1953-1971), Washington, D. C., United States of America (Source: Wikipédia).

Abelsonite (mineral collection and photography: Dr. Thomas Witzke, Almelo, Netherlands).

   Crystal system: triclinic and crystalline structure (RRUFF Project).

D Genesis: secondary mineral generated under unique geochemical conditions by salts of organic acids, derived from chlorophyll diagenesis. Transport of the relatively insoluble precursor material was mobilized by aquous solutions to favorable sediments that occur along fractures of kerogen-rich shales, may be associated with albite Na(AlSi₃O₈), analcime Na(AlSi₂O₆).H₂O, dolomite CaMg(CO₃)₂, orthoclase K(AlSi₃O₈), pyrite FeS₂,  and quartz SiO₂.  

Occurrence(s): United States of America (for more details, see Mindat.org in the page of mineral).

Reference(s):

NEVES, P. C. P. das; CORRÊA, D. S.; CARDOSO, J. C. A classe mineralógica das combinações orgânicas associadas ao hidrogênio. Terrae Didatica, v. 4, n. 1, pp. , 51-66, 2015.

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3. ABENAKIITE-(Ce) (Abk-Ce) - Na₂₆(Ce,REE)₆(SiO₃)_6(PO4)_6(CO3)6 (S⁴⁺O₂)O 

Chemical data and Nickel-Strunz classes: molecular mass = 2,903.93 gmol^1-; elemental contents: O = 34.71%, Ce = 28.95%, Na = 19.94%, P = 6.19%, Si = 5.63%, C = 2,41%, S = 2.17%; oxide contents: Ce₂O₃ = 33.89 %, Na₂O = 27.73%, P₂O₅ = 14.11%, SiO₂ = 12.41%, CO₂ = 9.09%, SO₂ = 2,77%. 

Silicates (Germanates), Cyclosilicates, [Si₆O₁₈]₁₂-6-membered single rings, with insular complex anions - 9.CK.10.

b) IMA status: validated species (1991). 

Type-locality(ies):

Proudette quarry, Mont Saint-Hilaire, La Valée-du-Richelieu, Montérégie, Québec, Canada.

Repository(ies) (type-material): Canadian Museum of Nature, Ottawa,  Ontario, Canada (catalog(s): 81,501).  

Name origin: 

in allusion to the indigenous tribe of the Abenaki, former inhabitants of the surroundings of Mount Saint-Hilaire (Source: Legends of America).

Images:

Abenakiite-(Ce) (indicated by the blue arrow), Proudette quarry, Mont Saint-Hilaire, La Valée–du-Richelieu, Montérégie, Québec, Canada (mineral collection and photograph: Lazló Horváth, Canada); panoramic image of Mount Saint-Hilaire (google images).

   Crystal system: trigonal and crystalline structure (RRUFF Project).

  Genesis: minerals that occur as xenoliths in sodalite syenite, as late-stage phases, possibly due to metasomatism (McDONALD et al., 1994). 

Occurrence(s): Canada and Russia (for more details, see Mindat.org in the page of mineral).

Reference(s):

McDONALD, A. M.; CHAO, G. Y.; GRICE, J. D. Abenakiite-(Ce), a new silicophosphate carbonate mineral from Mont Saint-Hilaire, Quebec: description and structure determination. The Canadian Mineralogist, v. 32, n. 4, pp. 843-854, 1994.

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4. ABERNATHYITE (Abn) - K[(UO₂)(AsO₄)]H₂O₃

Chemical data and Nickel-Strunz classes: molecular mass = 520.11 gmol^1-; elemental contents: U = 45.77%, O = 30.76%, As = 14.41%, K = 7.52%, H = 1.55%; oxide contents: UO₂ = 81.92 %, As₂O₃ = 22.10%, H₂O = 13.82%, K₂O = 9.06%, CO₂ = 9.09%, SO₂ = 2.77%. 

Arsenates - 8.EB.15.

b) IMA status: validated species (pre-IMA 1956). 

Type locality(ies):

Fumarola mine, Temple Mountain, San Rafael mining district, Emery Co., Utah, United States of America.

Repository(ies) (type-material): National Museum of Natural History, Washington, DC, United States of America (catalog(s): 112,650).  

Name origin: 

in honor to mine foreman Jesse Everett Abernathy (☼1913-┼1963), operator of the Fumarola mine, who first collected this species (Source: https://www.mindat.org/min-3.html).

Images:

Abernathyite (Excalibur Mineral Corp. mineral collection – photography: Jeffrey Weissman, New Haven, Connecticut, Unit States of America).

   Crystal system: tetragonal and crystalline structure (Source: RRUFF Project).

Genesis: secondary mineral that fills fractures in asphaltic sandstones and, in the oxidation zone of uranium deposits, may be associated with arsenium As,  heinrichite Ba(UO₂)₂(AsO₄)₂.10-12H₂O, jarosite KFe₃(SO₄)₂(OH)₆, metazeunerite Cu²⁺(UO₂)₂(AsO₄)₂.8H₂O, orpiment As₂S₃, pitticite [Fe³⁺,AsO₄,SO₄,H₂O]?, realgar As₄S₄, scorodite Fe³⁺AsO₄.2H₂O and zeunerite Cu²⁺(UO₂)₂(As O₄)₂.10-16H₂O.

Occurrence(s): France, Germany, Poland, South Africa Republic and United States of America (for more details, see Mindat.org in the page of mineral).

Reference(s):

THOMPSON, M. E.; INGRAM, B.; GROSS, E. B. Abernathyite, a new uranium mineral of the metatorbernite group. The American Mineralogist, v. 41, ns. 1-2, pp. 82-90, 1956.

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5.                       5. ABHURITE  - (Abh) - Sn²⁺₂₁O₆(OH)₁₄Cl₁₄

Chemical data and Nickel-Strunz classes: molecular mass = 477.05 gmol^1-; elemental contents: Sn = 74.77%, Cl = 14.86%, O = 10.06%, H = 0.42%; oxide contents: SnO = 84.71%, H₂O = 3.78%, Cl = 14,86%, -O=Cl₂ = -3,35%. 

Halides - 3.DA.30.

b)IMA status: validated species (1983). 

Type locality(ies):

Sharm Abhu cave, Jiddah, Mecca region, Saudi Arabia.

Repository(s) (type-material): Ontario Royal Museum, Toronto, Canada;  National Museum of Natural History, Washington, DC, United States of America (catalog(s): 162,403).  

Name origin: in alusion of type-locality.

Images:

Abhurite (The Arkestone minerals collection, i.Rocks.com – photography: Rob Lavinsky, Richardson, Texas, Unit States of America); SS Liverpool wrack at the bottom of the Atlantic Ocean, on the Isle of Anglesey, Great Britain (google images), where the mineral was found.

   Crystalline system: trigonal and crystalline structure 

g Genesis: Tin ingots corroded by sea water; usually as scabs on sunken ship hulls, may be associated with aragonite CaCO₃, kutnohorite (Ca(Mn²⁺,Mg,Fe²⁺)(CO₃)₂, and romarchite SnO.

Occurrence(s): England and United Kingdown (Wales), Jamaica, Norway, Saudi Arabia, and United States of America (for more details, see Mindat.org in the page of mineral).

Reference(s):

MATZKO, J. J.; EVANS, H. T.; MROSE, M. E.; ARUSCAVAGE, P. Abhurite, a new tin hydroxychloride mineral and a study a synthetic basic tin chloride. The Canadian Mineralogist, v. 23, n. 2, pp. 233-240, 1985.

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6. ABRAMOVITE  - (Abm) - Pb₂SnInBiS₇

Chemical data and Nickel-Strunz classes: molecular mass = 1,066.44 gmol^1-; elemental contents: Pb = 37.30%, S = 20.35%, Bi = 17.44%, Sn = 12,13%, In = 11.41%.  

Sulfosalts - 2.HF.25a.

b) IMA status: validated species (2006). 

Type locality(ies):

 Kudryav volcano, Iturub island, Kurilsky district, Kurile islands, Shakalin Oblast, Russia.

Repository(s) (type-material): A. E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia (catalog(s): 3436/1).

Name origin:   

in honor to Russian geologist and mineralogist Dmitry Vadimovich Abramov (☼1963).

f) Images:

 

Abramovite (collection and photography: Pavel Kartashov, Moscow, Russia), Kudryav volcano, Iturub island, district, Kurile islands, Shakalin Oblast, Russia. 

   Crystallline system: triclinic.

Genesis: in ingots corroded by sea water, may be associated with  anhydrite CaSO₄, galena PbS, halita NaCl, pyrrhotite Fe_1-xS, pyrite FeS₂,  sylvite KCl, and wurtzite (Zn,Fe)S (YUDOSVSKAYA et al., 2008).

Occurrence(s): Russia (for more details, see Mindat.org in the page of mineral).

Reference(s):

YUDOVSKAYA, M. A.; TRUBKIN, N. V.; KOPORULINA, E. V.; BELAKOVSKY, D. I.; MOKHOV, A. D.; KUSZNETSOVA, M. V.; GOLOVANOVA, T. I. Abramovite, Pb₂SnInBiS_7, a new mineral species from fumaroles of the Kudryavy volcano, Kurile islands, Russia. Geology of Ore Deposits, v. 50, n. 7, pp. 551-555, 2008.

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6.               7. ABSWURBACHITE  - (Abs) - CuMn³⁺₆(SiO₄)₈

Chemical data and Nickel-Strunz classes: molecular mass = 809.485 gmol^1-; elemental contents: Mn = 40.70%, Si = 27.74%, O = 23,71.29%, Cu = 7.85%; oxide contents:  Mn₂O₃ = 58.48%, SiO₂ = 31.70%, CuO = 9.82%.  

Silicates (Nesosilicates)  - 9.AG.05.

b) IMA status: validated species (1990). 

Type locality(ies):

Mili, Dirfys-Messapia, Euboea, Central Greece; Apikia,  Vasiliko Mountain, Andros, South Aegea, Greece.

Repository(s) (type-material): Institut für Geologie, Mineralogie & GeophysiK, Rühr Universität, Bochum, Germany; National Museum of Natural History, Washington, D. C., Unitad State of America.

Name origin:   

in honor to the German researcher Dr. Imgard  Abs-Wurmbach  (☼1938-┼2020) at the Rühr University. Above left, death notice of. Professor Imgard Abs-Wurmbach.

f) Images:

Abswurmbachite (collection and photography: Pavel Kartashov, Moscow, Russia), Mili, Andros island, Greece - diminutes black points.

   Crystallline system: tetragonal.

g)Genesis: in in very low-grade, high pressure metamorphic quartzites, may be associated with clinochlore Mg₅Al(Si₃O₁₀)(OH)₈, hollandite Ba(Mn⁴⁺₆Mn³⁺₂)O₁₆, piemontite (CaCa)(AlAlMn³⁺)O][Si₂O₇][SiO₄](OH), quartz SiO₂, rutile TiO₂, shattuckite  Cu₂(SiO₃)₄(OH)₂, surssasite Mn³⁺Al₃(SiO₄)(Si₂O₇)(OH)₃ and tenorite CuO (REINECK et al., 1991).

Occurrence(s): Greece (for more details, see Mindat.org in the page of mineral).

Reference(s):

REINECK, T.; TILLMANNS, E.; BERNHARDT, H. J.  Abswurmbachite, Cu²⁺Mn³⁺₆[O₈/SiO₄] a new mineral of the braunite group: natural occurrence. Synthesis and crystal structure. Neues Jahrbuch für Minerálogie, Abhandlugen, v. 163, pp. 117-143, 1991.

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                           8. ABUITE  - (Abu) - CaAl₂(PO₄)₂F₂

Chemical data and Nickel-Strunz classes: molecular mass = 321.98 gmol^1-; elemental contents: O = 39.75%, P = 19.24%, Al = 16,76%, Ca = 12.45%, F = 11,80%; oxide contents:  P₂O₅ = 44,08%, Al₂O₃ = 31,67%, CaO = 17,42%, F = 11,80%,  -O=F₂ = 4,97%.  

Phosphates  - 8.BO.

b) IMA status: validated species (2014). 

Type locality(ies):

Hinomaru Nako mine, Abu Co., Yamagushi Prefecture, Japan.

Repository(s) (type-material): Kitakyushu Museum of Natural History and Human History (catalog(s): KMNHM000003), Kitakyushu, Japan .

Name origin:   

in allusion to the Abu Co., Japan - panoramic vision of Abu bay (Source: Wikipedia).

f) Images:

Abuite (collection and photography: Daisuki Nishio-Hamane, Japan).

   Crystallline system: orthorhombic.

g)Genesis: in hydrothermally altered, felsic pyroclastic rocks, related to a biotite adamellite intrusion, may be associated with "apatite", augelite Al₂(PO₄)(OH)₃, crandallite CaAl₃(PO₄)(PO₃OH)(OH)₆, quartz SiO₂, and trolleite Al₄(PO₄)₃(OH)₃  (ENJU; UCHARA, 2017).

Occurrence(s): Japan (for more details, see Mindat.org in the page of mineral).

Reference(s):

ENJU, S.; UCHARA, S. Abuite, CaAl₂(PO₄)₂F₂, a new mineral from the Hinomaru-Nago mine, Yamaguchi Prefecture, Japan. Journal of Mineralogy and Petrolology Sciences, v. 112, n. 1, pp. 109- 115, 2017.

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8.                          9. ACANTHITE  - (Aca) - Ag_2S

Chemical data and Nickel-Strunz classes: molecular mass = 247.80 gmol^1-; elemental contents: Ag = 87.60%, S = 12.94%.  

Sulfides  - 2.BA.35.

b) IMA status: validated species (pré-IMA 1855). 

Type locality(ies):

Jáchymov, Karlovy Vary district, Karlov Vary region, Tchéquia.

Repository(s) (type-material): Empero's collection (catalog(s): 2592), Vienna, Áustria.

Name origin:   

From the Greek "akantha" meaning "thorn", in allusion to the thorn-like crystal shape of his material.

f) Images:

Acanthite (collection and photography: Paulo Neves, Brazil).

  

 Crystallline system: monoclinic and crystalline structure.

g)Genesis:  a common silver species in moderately low-temperature hydrothermal sulphide veins, and in zones of secondary enrichment, may be associated with aguilarite Ag₄SeS, calcite CaCO₃, chalcopyrite CuFeS₂, galena PbS, polybasite [Ag₉CuS₄][(Ag,Cu)₆(Sb,As)₂S₇], proustite Ag₃SbS₃, pyrargyrite Ag₃SbS₃, quartz SiO₂, silver Ag,  Al₂(PO₄)(OH)₃, sphalerite ZnS, and stephanite Ag₅SbS₄ (PALACHE et al., 1944).

Occurrence(s): Argentina, Armenia, Atlantic Ocean, Australia, Azerbaijan,  Belgium, Bolivia,  Bosnia & Herzegovina, Botswana, Brazil, Bulgaria,  Canada, Chile, Colombia, Cuba, Denmark (Greenland), Djibouti, Ecuador, Egypt,  El Salvador, Figi, Finland, France, Georgia, Germany, Greece, Guatemala, Honduras, Hungary, Indian, Indonesia, Iran, Iraq, Ireland, Israel, Italy, Japan, Jordan, Kazakhstan, Kyrgyzstan, Madagascar, Mali, Mexico, Mongolia, Morocco, Myanmar, Namibia, New Zeland, Nicaragua, Norway, Pacific Ocean, Panama,  Papua New Guine, Peru, Poland, Portugal, Romania, Russia, Saudi Arabia, Slovakia, Slovenia, South Africa, South Korea,   Spain, Sweden, Switzerland, Tajikistan, Tanzania, Tchequia, The Moon, Turkey, United Kingdon, Ukraine, United States of America, Uzbekistan,  Vietnam, and Yemen (for more details, see Mindat.org in the page of mineral). 

Obs: all natural silver sulphide specimens at room temperatures are acanthite. The structure of argentite, the high-temperature form cannot be quenched. At atmospheric pressure, argentite is stable above 177°C and acanthite is stable below its temperature. Most acanthite crystals are paramorphs, which formed above the transition temperature and retain an isometric shape below the transition temperature, but have monoclinic symetry at the atomic level. 

 

Reference(s):

PALACHE, C.; BERMAN, H.; FRONDEL, C. Dana’s system of mineralogy, (7th ed.), v. I, pp. 191–192 (acanthite), pp. 176–178 (“argentite”).

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                           10. ACETAMIDE  - (Ace) - CH₃CONH₂

Chemical data and Nickel-Strunz classes: molecular mass = 59.07 gmol^1-; elemental contents: C = 40.67%, O = 27,09%, N = 23.71%,  H = 8.53%.

Organic Compounds  - 10.AA.20

b) IMA status: validated species (1974). 

Type locality(ies):

Coal mine, Chervonograd, L'iviv-Volynkii Coal Basin,  Liviv Oblast, Ukraine.

Repository(s) (type-material): Mining Museum,  Saint Petersbug Mining Institute, Saint Petersburg; A. E. Fersman Mineralogical Museum, Academy of Sciences, Moscou, Russia.

Name origin:   in allusion to its chemical composition.

f) Images:

Acetamide (Excalibur Min. Comp.; photography: Dr. Jeff Weissman, New Haven, United States of America).

   

Crystallline system: Trigonal and crystalline structure.

g)Genesis: in burning waste coal heaps, formed between 50°C and 150°C., may be associated with salammoniac NH₄Cl (SREBRODOL'KII, B. I. , 1975).

Occurrence(s): Poland, Ukraine, and United States of America (for more details, see Mindat.org in the page of mineral).

Reference(s):

SREBRODOL'KII, B. I. (1975) Acetamide CH₃CONH₂ – a new mineral. Zapiski. Vserossyskogo Mineralogicheskogo Obshchestva, v. 104, n. 3, pp. 326–328, 1975.

c)

c)