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About MicrosommiteHide

colourless, white
Crystal System:
Named in 1872 by A. Scacchi. Name derived from 'micro' for the small crystal size and the type locality of Monte Somma, Italy.

Classification of MicrosommiteHide

Approved, 'Grandfathered' (first described prior to 1959)

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
B : Tektosilicates with additional anions

76 : TECTOSILICATES Al-Si Framework
2 : Al-Si Framework Feldspathoids and related species

17 : Silicates Containing other Anions
10 : Silicates with sulphate, molybdate or tungstate

Physical Properties of MicrosommiteHide

colourless, white

Optical Data of MicrosommiteHide

Uniaxial (+)
RI values:
nω = 1.521 nε = 1.529
Max Birefringence:
δ = 0.008
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of MicrosommiteHide

IMA Formula:

Crystallography of MicrosommiteHide

Crystal System:
Cell Parameters:
a = 22.08 Å, c = 5.33 Å
a:c = 1 : 0.241
Unit Cell V:
2,250.38 ų (Calculated from Unit Cell)

Type Occurrence of MicrosommiteHide

Synonyms of MicrosommiteHide

Other Language Names for MicrosommiteHide

Relationship of Microsommite to other SpeciesHide

Other Members of this group:
Afghanite(Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6Trig. 3m : P3 1c
Alloriite(Na,Ca,K)26Ca4(Al6Si6O24)4(SO4)6Cl6Trig. 3m : P3 1c
Balliranoite(Na,K)6Ca2(Si6Al6O24)Cl2(CO3)Hex. 6 : P63
Biachellaite(Na,Ca,K)8(Al6Si6O24)(SO4)2(OH)0.5 · H2OTrig. 3 : P3
Cancrinite(Na,Ca,☐)8(Al6Si6O24)(CO3,SO4)2 · 2H2OHex. 6 : P63
CancrisiliteNa7(Al5Si7O24)(CO3) · 3H2OHex.
Davyne(Na,K)6Ca2(Al6Si6O24)(Cl2,SO4)2Hex. 6/m : P63/m
DepmeieriteNa8(Al6Si6O24)(PO4,CO3)1-x · 3H2O (x<0.5)Hex. 6 : P63
Franzinite(Na,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2OHex.
HydroxycancriniteNa8(Al6Si6O24)(OH)2 · 2H2OHex.
KircheriteNa5Ca2K(Al6Si6O24)(SO4)2 · 0.33H2OTrig. 3 2 : R3 2
KyanoxaliteNa7(Al6-xSi6+xO24)(C2O4)0.5+x · 5H2O (0 < x < 0.5)Hex. 6 : P63
Marinellite(Na,K)42Ca6(Al6Si6O24)6(SO4)8Cl2 · 3H2OTrig. 3m : P3 1c
PitiglianoiteNa6K2(Al6Si6O24)(SO4) · 2H2OHex.
SulfhydrylbystriteNa5K2Ca[Al6Si6O24](S5)2(SH)Trig. 3m : P3 1c
Tounkite(Na,Ca,K)8(Al6Si6O24)(SO4)2Cl · H2OHex.
Vishnevite(Na,K)8(Al6Si6O24)(SO4,CO3) · 2H2OHex. 6 : P63

Common AssociatesHide

Associated Minerals Based on Photo Data:
Sanidine2 photos of Microsommite associated with Sanidine on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.FB.05Afghanite(Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6Trig. 3m : P3 1c
9.FB.05Cancrinite(Na,Ca,☐)8(Al6Si6O24)(CO3,SO4)2 · 2H2OHex. 6 : P63
9.FB.05CancrisiliteNa7(Al5Si7O24)(CO3) · 3H2OHex.
9.FB.05Davyne(Na,K)6Ca2(Al6Si6O24)(Cl2,SO4)2Hex. 6/m : P63/m
9.FB.05Franzinite(Na,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2OHex.
9.FB.05HydroxycancriniteNa8(Al6Si6O24)(OH)2 · 2H2OHex.
9.FB.05PitiglianoiteNa6K2(Al6Si6O24)(SO4) · 2H2OHex.
9.FB.05Tounkite(Na,Ca,K)8(Al6Si6O24)(SO4)2Cl · H2OHex.
9.FB.05Vishnevite(Na,K)8(Al6Si6O24)(SO4,CO3) · 2H2OHex. 6 : P63
9.FB.05Marinellite(Na,K)42Ca6(Al6Si6O24)6(SO4)8Cl2 · 3H2OTrig. 3m : P3 1c
9.FB.05Farneseite(Na,Ca,K)56(Al6Si6O24)7(SO4)12 · 6H2OHex. 6/m : P63/m
9.FB.05Alloriite(Na,Ca,K)26Ca4(Al6Si6O24)4(SO4)6Cl6Trig. 3m : P3 1c
9.FB.05Fantappièite[Na82.5Ca33K16.5](Si99Al99O396)(SO4)33 · 4H2OTrig. 3 : R3
9.FB.05KyanoxaliteNa7(Al6-xSi6+xO24)(C2O4)0.5+x · 5H2O (0 < x < 0.5)Hex. 6 : P63
9.FB.05Balliranoite(Na,K)6Ca2(Si6Al6O24)Cl2(CO3)Hex. 6 : P63
9.FB.05CarbobystriteNa8(Al6Si6O24)(CO3) · 3.5H2OTrig. 3m : P3 1c
9.FB.05DepmeieriteNa8(Al6Si6O24)(PO4,CO3)1-x · 3H2O (x<0.5)Hex. 6 : P63
9.FB.05KircheriteNa5Ca2K(Al6Si6O24)(SO4)2 · 0.33H2OTrig. 3 2 : R3 2
9.FB.10BicchuliteCa2(Al2SiO6)(OH)2Iso. 4 3m : I4 3m
9.FB.10DanaliteBe3Fe2+4(SiO4)3SIso. 4 3m : P4 3n
9.FB.10GenthelviteBe3Zn4(SiO4)3SIso. 4 3m : P4 3n
9.FB.10Haüyne(Na,K)3(Ca,Na)(Al3Si3O12)(SO4,S,Cl)Iso. 4 3m : P4 3n
9.FB.10HelvineBe3Mn2+4(SiO4)3SIso. 4 3m : P4 3n
9.FB.10LazuriteNa6Ca2(Al6Si6O24)(SO4,S,S2, S3,Cl,OH)2Iso. 4 3m : P4 3n
9.FB.10NoseanNa8(Al6Si6O24)(SO4) · H2OIso. 4 3m : P4 3n
9.FB.10SodaliteNa8(Al6Si6O24)Cl2Iso. 4 3m : P4 3n
9.FB.10TugtupiteNa4BeAlSi4O12ClTet. 4 : I4
9.FB.15MarialiteNa4Al3Si9O24ClTet. 4/m : I4/m
9.FB.15MeioniteCa4Al6Si6O24CO3Tet. 4/m : I4/m
9.FB.15Silvialite(Ca,Na)4(Al6Si6O24)(SO4,CO3)Tet. 4/m : I4/m

Related Minerals - Dana Grouping (8th Ed.)Hide,K)22Ca10(Si24Al24O96)(SO4)6Cl6Trig. 3m : P3 1c,K)7Ca(Al6Si6O24)(S5)ClHex.,Ca,☐)8(Al6Si6O24)(CO3,SO4)2 · 2H2OHex. 6 : P63 · 3H2OHex.,K)6Ca2(Al6Si6O24)(Cl2,SO4)2Hex. 6/m : P63/m,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2OHex.,K,Ca)7-8(Al6Si6O24)(SO4,Cl)1-2Hex. · 2H2OHex.,K)16Ca8(Al6Si6O24)3(SO4)5Cl4Hex. · 2H2OHex.,K)6Ca2(Al6Si6O24)Cl4Hex.•2H2OHex.,Ca,K)8(Al6Si6O24)(SO4)2Cl · H2OHex.,K)8(Al6Si6O24)(SO4,CO3) · 2H2OHex. 6 : P63,K)4(Ca,Na)6[(SO4)3|(Si,Al)20O39(OH)2] · 0.5H2OHex.

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

17.10.1NoseanNa8(Al6Si6O24)(SO4) · H2OIso. 4 3m : P4 3n
17.10.2PitiglianoiteNa6K2(Al6Si6O24)(SO4) · 2H2OHex.
17.10.3Vishnevite(Na,K)8(Al6Si6O24)(SO4,CO3) · 2H2OHex. 6 : P63
17.10.4Haüyne(Na,K)3(Ca,Na)(Al3Si3O12)(SO4,S,Cl)Iso. 4 3m : P4 3n
17.10.7Tuscanite(K(Ca,Na)6(Si,Al)10O22[SO4,CO3,(OH)2] · H2OMon.
17.10.9Delhayelite(Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2OOrth.
17.10.10HydrodelhayeliteKCa2AlSi7O17(OH)2 · 6H2OOrth.
17.10.11Davyne(Na,K)6Ca2(Al6Si6O24)(Cl2,SO4)2Hex. 6/m : P63/m
17.10.12Afghanite(Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6Trig. 3m : P3 1c
17.10.13Franzinite(Na,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2OHex.
17.10.16Chessexite(Na,K)4Ca2(Mg,Zn)3Al8(SO4)10(SiO4)2 · 40H2OOrth.
17.10.17InneliteNa2CaBa4Ti3(Si2O7)2(SO4)2O4Tric. 1 : P1
17.10.18ThaumasiteCa3(SO4)[Si(OH)6](CO3) · 12H2OHex. 6 : P63
17.10.20ChlorellestaditeCa5(SiO4)1.5(SO4)1.5ClHex. 6/m : P63/m
17.10.21HydroxylellestaditeCa5(SiO4)1.5(SO4)1.5(OH)Hex. 6/mmm (6/m 2/m 2/m) : P63/mcm
17.10.23MattheddleitePb5(SiO4)1.5(SO4)1.5(Cl,OH)Hex. 6/m : P63/m
17.10.24QueititePb4Zn2(SO4)(SiO4)(Si2O7)Mon. 2 : P21
17.10.25RoeblingitePb2Ca6Mn2+(Si3O9)2(SO4)2(OH)2 · 4H2OMon. 2/m : B2/m
17.10.26YoshimuraiteBa2Mn2Ti(Si2O7)(PO4)O(OH)Tric. 1 : P1
17.10.28Wenkite(Ba,K)4(Ca,Na)6[(SO4)3|(Si,Al)20O39(OH)2] · 0.5H2OHex.
17.10.30WeliniteMn2+6(W6+,Mg)2(SiO4)2(O,OH)6Trig. 3 : P3

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for MicrosommiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Scacchi, A. (1872) Notizie preliminari di alcune specie mineralogiche rinvenute nel Vesuvio dopo l'incendio di aprile 1872. Rendiconto dell'Accademia delle Scienze Fisiche e Matematiche (sezione della Società reale di Napoli): 11: 210-213.
Scacchi, A. (1873) Contribuzioni mineralogiche per servire alla storia dell’ incendio Vesuviano del Mese di Aprile, 1872. Part 2. Reale Accademia delle Scienze Fisische e Matematiche Naples: 1-69.
vom Rath, G. (1874) Über den Mikrosommit. Annalen der Physik und Chemie, Erg. Bd. VI, J.C. Poggendorff, Leipzig: 372-376.
Bariand, P. Cesbron, F., Giraud, R. (1968) Une nouvelle espèce minerale: L'afghanite de Sar-e-Sang, Badakhshan, Afghanistan. Comparison avec les minéreaux du groupe de la cancrinite. Bulletin de la Société française de Minéralogie et de Cristallographie: 91: 34.
Rinaldi, R., Wenk, H.R. (1979) Stacking variations in cancrinite minerals. Acta Crystallographica: A35: 825-828.
Leoni, L., Mellini, M., Merlino, S., Orlandi, P. (1979) Cancrinite-like minerals: new data and crystal chemical considerations. Rendiconti della Società Italiana di Mineralogia e Petrologia: 35: 713-719.
Hassan, I., Grundy, H.D. (1984) The crystal structures of sodalite-group minerals. Acta Crystallographica: B40: 6-13.
Hassan, I., Grundy, H.D. (1990) Structure of davyne and implications for stacking faults. Canadian Mineralogist: 28: 341.
Ballirano, P., Maras, A., Buseck, P.R. (1996) Crystal chemistry and IR spectroscopy of Cl- and SO4-bearing cancrinite-like minerals. American Mineralogist: 81: 1003-1012.

Internet Links for MicrosommiteHide

Localities for MicrosommiteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Auvergne-Rhône-Alpes
    • Puy-de-Dôme
      • Pontgibaud
        • Saint-Ours-les-Roches
Médard P. et al. (2009) La pseudobrookite du Puy de Tunisset (Puy-de-Dôme). Le Cahier des Micromonteurs 105: 3-11.
  • Campania
    • Naples Province
      • Somma-Vesuvius Complex
        • Monte Somma
          • Pollena - Trocchia area
Mateo Chinelatto photo
          • Sant'Anastasia
M. Carati - Guida alla mineralogia vesuviana - Calderini, Bologna, 1982
Rath, G. vom, 1874: Über den Mikrosommit, Annalen der Physik und Chemie, Erg. Bd. VI, 372-376, J.C. Poggendorff, Leipzig
          • Terzigno
Samples analysed by Dr. Tony Kampf, Curator of LAC Mineralogical Museum, USA; Chukanov, N.V., Chervonnyi, A.D. (2016): Infrared spectroscopy of minerals and related compounds. Springer, Cham Heidelberg Dordrecht New York London, pages 477-478.
    • Phlegrean Volcanic Complex
      • Salerno Province
        • Nocera Inferiore
Scacchi, A. (1881): Notizie preliminari intorno ai proietti vulcanici di Nocera e Sarno. Atti della R. Accademia dei Lincei, serie 3, Transunti, 5 (1880-81), 270-273; Scacchi, A. (1885): La regione vulcanica fluorifera della Campania. Atti della R. Accademia delle Scienze fisiche e matematiche di Napoli, serie 2, 2 (1888), 108 pp.; Scacchi, A. (1890): La regione vulcanica fluorifera della Campania. Memorie del R. Comitato Geologico Italiano, 4, 1-52; Zambonini, F. (1913): Grothina, un nuovo minerale. Atti della R. Accademia dei Lincei, serie 5, Rendiconti, 22, 1, 801-803; Zambonini, F. (1919): Il tufo piperinoide della Campania e i suoi minerali. Memorie per servire alla descrizione della Carta geologica d'Italia, 7, 2, 130 pp.; Carati, M. (1988): I minerali degli inclusi metamorfosati nel Tufo Grigio Campano. Notiziario del Gruppo Mineralogico Geologico Napoletano, 18, 5-12.
  • Tuscany
    • Grosseto Province
      • Pitigliano
Gentile P. (1985): Microsommite di Pitigliano (GR). Riv. Mineral. Ital., 9, 4 (4-1985), 146; Liotti L. (1991): I minerali dei vulcani laziali a Pitigliano (Grosseto). Riv. Mineral. Ital., 15, 3 (3-1991), 121-139.
  • Viloyati Mukhtori Gorno-Badakhshan (Viloyati Badakhshoni Kuni)
    • Pamir Mts
Solovova, I. P., Girnis, A. V., Ryabchikov, I. D., & Simakin, S. G. (2006, October). High-temperature carbonatite melt and its interrelations with alkaline magmas of the Dunkel’dyk complex, southeastern Pamirs. In Doklady earth sciences (Vol. 410, No. 1, pp. 1148-1151). MAIK Nauka/Interperiodica.
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