Fivegite
A valid IMA mineral species
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About Fivegite
Formula:
K4Ca2[AlSi7O17(O2-xOHx)][(H2O)2-xOHx]Cl
Colour:
Colourless
Lustre:
Vitreous, Pearly
Hardness:
4
Specific Gravity:
2.42
Crystal System:
Orthorhombic
Member of:
Name:
Named for Russian geologist and mine engineer Mikhail Pavlovich Fiveg (Михаил Павлович Фивег) (8 (20) September 1899, Divensky, St. Petersburg province, Russian Empire - 11 January 1986, Leningrad, USSR), specialist in nonmetallic mineral deposits, especially apatite, who lead the first prospecting team for apatite in the Khibiny massif (1928-1933).
Unique Identifiers
Mindat ID:
39711
Long-form identifier:
mindat:1:1:39711:5
GUID
(UUID V4):
(UUID V4):
a7bfdf4d-6746-4762-be67-b42a0f33114c
IMA Classification of Fivegite
Approved
IMA Formula:
K4Ca2[AlSi7O17(O2-x(OH)x)][(H2O)2-x(OH)x]Cl (x = 0-2)
Approval year:
2009
First published:
2010
Classification of Fivegite
9.EB.30
9 : SILICATES (Germanates)
E : Phyllosilicates
B : Double nets with 4- and 6-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
B : Double nets with 4- and 6-membered rings
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Fiv | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Fivegite
Vitreous, Pearly
Transparency:
Transparent
Colour:
Colourless
Streak:
White
Hardness:
4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {100} and distinct on {010}
Perfect on {100} and distinct on {010}
Fracture:
Step-Like
Density:
2.42(2) g/cm3 (Measured) 2.449 g/cm3 (Calculated)
Optical Data of Fivegite
Type:
Biaxial (+)
RI values:
nα = 1.540(1) nβ = 1.542(2) nγ = 1.544(2)
2V:
Measured: 60° (10)
Max Birefringence:
δ = 0.004
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Pleochroism:
Non-pleochroic
Chemistry of Fivegite
Mindat Formula:
K4Ca2[AlSi7O17(O2-xOHx)][(H2O)2-xOHx]Cl
Crystallography of Fivegite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pmn21
Cell Parameters:
a = 24.335(2) Å, b = 7.0375(5) Å, c = 6.5400(6) Å
Ratio:
a:b:c = 3.458 : 1 : 0.929
Unit Cell V:
1120 ų
Z:
2
Comment:
Space group setting: Pm21n
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.517 Å | (38) |
| 3.072 Å | (100) |
| 3.040 Å | (46) |
| 2.943 Å | (47) |
| 2.893 Å | (53) |
| 2.880 Å | (41) |
| 2.759 Å | (25) |
| 1.759 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Fivegite
General Appearance of Type Material:
Pseudomorphs after roughly formed prismatic (with pyramidal termination) delhayelite crystals up to 2 × 3 × 10 cm in size and their intergrowths.
Place of Conservation of Type Material:
Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia (registration number 3881/1).
Geological Setting of Type Material:
In a hyperalkaline pegmatite body hosted in urtite close to the contact with nepheline–apatite rock. Fivegite is a secondary mineral that replaces delhayelite.
Associated Minerals at Type Locality:
Synonyms of Fivegite
Relationship of Fivegite to other Species
Member of:
Other Members of this group:
| Delhayelite | (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O | Orth. |
| Hydrodelhayelite | KCa2AlSi7O17(OH)2 · 6H2O | Orth. mm2 |
| Melansonite | Na◻KZrSi8O19 · 5H2O | Orth. mmm (2/m 2/m 2/m) : Pmma |
| Monteregianite-(Y) | (Na,K)6(Y,Ca)2Si16O38 · 10H2O | Mon. 2/m |
| Natromelansonite | Na3Zr[Si7AlO19] · 4H2O | Mon. 2/m : P21/m |
| Rhodesite | KHCa2Si8O19 · 5H2O | Orth. mmm (2/m 2/m 2/m) |
Common Associates
Associated Minerals Based on Photo Data:
| 3 photos of Fivegite associated with Aegirine | NaFe3+Si2O6 |
| 2 photos of Fivegite associated with Eudialyte | Na15Ca6Fe3Zr3Si(Si25O73)(O,OH,H2O)3(Cl,OH)2 |
| 2 photos of Fivegite associated with Lovozerite | Na2Ca(Zr,Ti)(Si6O12)[(OH)4O2] · H2O |
| 2 photos of Fivegite associated with Nepheline | Na3K(Al4Si4O16) |
| 2 photos of Fivegite associated with Sodalite | Na4(Si3Al3)O12Cl |
| 1 photo of Fivegite associated with Delhayelite | (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O |
Related Minerals - Strunz-mindat Grouping
| 9.EB. | Natromelansonite | Na3Zr[Si7AlO19] · 4H2O |
| 9.EB.05 | Macdonaldite | BaCa4Si16O36(OH)2 · 10H2O |
| 9.EB.05 | Rhodesite | KHCa2Si8O19 · 5H2O |
| 9.EB.05 | Melansonite | Na◻KZrSi8O19 · 5H2O |
| 9.EB.10 | Delhayelite | (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 · 18H2O |
| 9.EB.10 | Hydrodelhayelite | KCa2AlSi7O17(OH)2 · 6H2O |
| 9.EB.15 | Monteregianite-(Y) | (Na,K)6(Y,Ca)2Si16O38 · 10H2O |
| 9.EB.20 | Carletonite | KNa4Ca4Si8O18(CO3)4(OH,F) · H2O |
| 9.EB.20 | Fluorcarletonite | KNa4Ca4Si8O18(CO3)4F · H2O |
| 9.EB.25 | Günterblassite | (K,Ca,Ba)2(Fe,Ca,Mg,Na)[(Si,Al)13O25(OH)4] · 7H2O · |
| 9.EB.25 | Umbrianite | K7Na2Ca2[Al3Si10O29]F2Cl2 |
| 9.EB.25 | Hillesheimite | (K,Ca,Ba,◻)2(Mg,Fe,Ca,◻)2[(Si,Al )13O23(OH)6](OH) · 8H2O |
Fluorescence of Fivegite
Strong pink under LW UV and white with a lilac tint under SW UV. Non-fluorescent variety of fivegite was also identified.
Other Information
Notes:
Fivegite is less brittle than delhayelite; its fine plates (fragments of splitting) are able to bend slightly but generally remain inelastic.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Fivegite
mindat.org URL:
https://www.mindat.org/min-39711.html
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References for Fivegite
Reference List:
Localities for Fivegite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and 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).
All localities listed without proper references should be considered as questionable.
Russia (TL) | |
| Pekov I.V. et al. (O2-xOHx) +1 other reference |
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Tsentral'nyi Mine, Rasvumchorr Mine, Rasvumchorr Mt, Khibiny Massif, Murmansk Oblast, Russia