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About MegacycliteHide

Na8KSi9O18(OH)9 · 19H2O
Vitreous, Sub-Vitreous
Specific Gravity:
Crystal System:
The name is from the Greek for 'large' and 'cyclical', alluding to the structure of large, ringlike groups consisting of 18Si04 tetrahedra.
This page provides mineralogical data about Megacyclite.

Classification of MegacycliteHide


9 : SILICATES (Germanates)
C : Cyclosilicates
P : 12-membered and larger rings

62 : CYCLOSILICATES Eight-Membered Rings
1 : Eight-Membered Rings with 8-membered and larger rings

Physical Properties of MegacycliteHide

Vitreous, Sub-Vitreous
Perfect {100},less perfect {001}
1.82(5) g/cm3 (Measured)    1.87 g/cm3 (Calculated)

Optical Data of MegacycliteHide

Biaxial (-)
RI values:
nα = 1.460 nβ = 1.478 nγ = 1.481
Measured: 44° , Calculated: 44°
Max Birefringence:
δ = 0.021
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
r > v strong

Chemical Properties of MegacycliteHide

Na8KSi9O18(OH)9 · 19H2O
IMA Formula:
KNa8Si9O18(OH)9 · 19H2O

Crystallography of MegacycliteHide

Crystal System:
Cell Parameters:
a = 24.91 Å, b = 11.94 Å, c = 14.92 Å
β = 94.47°
a:b:c = 2.086 : 1 : 1.25
Unit Cell V:
4,424.09 ų (Calculated from Unit Cell)

Type Occurrence of MegacycliteHide

Place of Conservation of Type Material:
Mining Institute, St..Petersburg, 2066/1.
A.E. Fersman Mineralogical Museum, Academy of Science, Moscow, Russia, p733/2.

Synonyms of MegacycliteHide

Other Language Names for MegacycliteHide

Related Minerals - Nickel-Strunz GroupingHide

9.CP.05TraskiteBa21Ca(Fe2+,Mn,Ti)4(Ti,Fe,Mg)12(Si12O36)(Si2O7)6(O,OH)30Cl6·14H2O Hex.

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 MegacycliteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Khomyakov, A.P., Necheljustov, G.N., Yamnova, N.A., Pushcharovsky, D.Y. (1993) Megacyclite Na8KSi9O18(OH)9·19H2O — a new mineral. Zapiski Vserossijskogo Mineralogicheskogo Obshchestva: 122(1): 125-128.
Jambor, J.L., Roberts, A.C., Vanko, D.A. (1994) New mineral names. American Mineralogist: 79: 1009-1014.
New Minerals (1997), New Minerals 1990-1994.
Zubkova, N.V., Pekov, I.V., Chukanov, N.V., Listsin, D.V., Rabadanov, M.K., Pushcharovsky, D.Y. (2007) New data on megacyclite. New Data on Minerals. Moscow: 42: 81-92.
Krivovichev, S.V. (2013) Structural complexity of minerals: information storage and processing in the mineral world. Mineralogical Magazine: 77: 275-326.
Zubkova, N.V., Pekov, I.V., Pushcharovsky, D.Y. (2014) A review of crystal chemistry of natural silicates of alkaline elements in the light of new structural data. Mineralogical Magazine: 78: 253-265.

Internet Links for MegacycliteHide

Localities for MegacycliteHide

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.
Russia (TL)
  • Murmansk Oblast
    • Khibiny Massif
Am Min 79:1011; Pekov, I. (1998) Minerals First discovered on the territory of the former Soviet Union 369p. Ocean Pictures, Moscow
        • Rasvumchorr Mine
Pekov I.V., Zubkova N.V., Filinchuk Ya.E., Chukanov N.V., Zadov A.E., Pushcharovsky D.Yu., Gobechiya E.R. (2010): Shlykovite, KCa[Si4O9(OH)]·3H2O, and cryptophyllite, K2Ca[Si4O10]·5H2O, two new mineral species from the Khibiny alkaline complex, Kola Peninsula, Russia. Zapiski RMO, 139(1), 37-50.
    • Lovozero Massif
      • Kedykverpakhk Mt
        • Karnasurt mine (Kedyk area)
Pekov I.V.. et al. (2009) Egorovite Na4[Si4O8(OH)4]·7H2O - new mineral from Lovozero alkaline massif (Kola peninsula) - Zapiski RMO, v. 138, №3, pp. 82-89 (in Rus.)
Mineral and/or Locality  
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