Melanophlogite
A valid IMA mineral species
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About Melanophlogite
Formula:
46SiO2 · 6(N2,CO2) · 2(CH4,N2)
Colour:
Colorless, white, water-clear (pale yellow to deep red brown with impurities)
Lustre:
Adamantine
Hardness:
6½ - 7
Specific Gravity:
1.99 - 2.11
Crystal System:
Tetragonal
Member of:
Name:
Named in 1876 by A. von Lasaulx for the Greek words for 'black' and 'to be burned' because some specimens turn black when heated.
Type Locality:
Unique Identifiers
Mindat ID:
2630
Long-form identifier:
mindat:1:1:2630:3
IMA Classification of Melanophlogite
Approved
IMA Formula:
C2H17O5 · Si46O92
First published:
1876
Classification of Melanophlogite
4.DA.25
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
A : With small cations: Silica family
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
A : With small cations: Silica family
75.2.2.1
75 : TECTOSILICATES Si Tetrahedral Frameworks
2 : Si Tetrahedral Frameworks - SiO2 with H2O and organics
75 : TECTOSILICATES Si Tetrahedral Frameworks
2 : Si Tetrahedral Frameworks - SiO2 with H2O and organics
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 for Standard |
|---|---|---|
| Mp | 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 Melanophlogite
Adamantine
Transparency:
Transparent, Translucent
Colour:
Colorless, white, water-clear (pale yellow to deep red brown with impurities)
Streak:
White
Hardness:
6½ - 7 on Mohs scale
Hardness:
VHN100=649 - 724 kg/mm2 - Vickers
Tenacity:
Brittle
Fracture:
Conchoidal
Density:
1.99 - 2.11 g/cm3 (Measured) 1.98 g/cm3 (Calculated)
Optical Data of Melanophlogite
Type:
Isotropic
RI values:
n = 1.425 - 1.457
Birefringence:
Isotropic minerals have no birefringence
Surface Relief:
Moderate
Comments:
may be weakly anisotropic.
Chemistry of Melanophlogite
Mindat Formula:
46SiO2 · 6(N2,CO2) · 2(CH4,N2)
Element Weights:
Common Impurities:
ORG,C,H,S
Crystallography of Melanophlogite
Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Cell Parameters:
a = 26.82(3) Å, c = 13.37(2) Å
Ratio:
a:c = 1 : 0.499
Unit Cell V:
9,617.21 ų (Calculated from Unit Cell)
Z:
184
Twinning:
Interpenetrant twinning on {201}, probable, giving sectored and depressed cube faces
Comment:
pseudocubic; Space Group: P4232
Crystallographic forms of Melanophlogite
Crystal Atlas:
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Melanophlogite no.2 - {100} - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0004493 | Melanophlogite | Tribaudino M, Artoni A, Mavris C, Bersani D, Lottici P P, Belletti D (2008) Single-crystal X-ray and Raman investigation on melanophlogite from Varano Marchesi (Parma, Italy) American Mineralogist 93 88-94 |  | 2008 | Case Montanini, Varano Marchesi, Parma, Italy | 0 | 293 |
| 0002748 | Melanophlogite | Nakagawa T, Kihara K, Harada K (2001) The crystal structure of low melanophlogite American Mineralogist 86 1506-1512 | | 2001 | 0 | 293 | |
| 0010856 | Melanophlogite | Gies H (1983) Studies on clathrasils. III. Crystal structure of melanophlogite, a natural clathrate compound of silica Zeitschrift fur Kristallographie 164 247-257 | | 1983 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.99 Å | (10) |
| 3.580 Å | (9) |
| 5.471 Å | (7) |
| 3.862 Å | (6) |
| 3.248 Å | (6) |
| 3.716 Å | (5) |
| 3.158 Å | (5) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 13 : Hadean serpentinization | |
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Type Occurrence of Melanophlogite
General Appearance of Type Material:
Light-brownish cubes to about 1 mm and aggregates forming chains and shells.
Place of Conservation of Type Material:
Natural History Museum, Paris, France, 135245.
Harvard University, Cambridge, Massachusetts, USA.
National Museum of Natural History, Washington, D.C., USA, C1279,93011.
Harvard University, Cambridge, Massachusetts, USA.
National Museum of Natural History, Washington, D.C., USA, C1279,93011.
Associated Minerals at Type Locality:
Other Language Names for Melanophlogite
Relationship of Melanophlogite to other Species
Member of:
Other Members of Silica:
| Chibaite | SiO2 · n(CH4, C2H6, C3H8, i-C4H10) (n = 3/17 (max)) | Iso. m3 (2/m 3) : Fd3 |
| Coesite | SiO2 | Mon. 2/m : B2/b |
| Cristobalite | SiO2 | Tet. 4 2 2 : P41 21 2 |
| 'Keatite' | SiO2 | Tet. 4 2 2 : P43 21 2 |
| Lechatelierite | SiO2 | Amor. |
| Mogánite | SiO2 | Mon. 2/m |
| 'Opal-AG' | SiO2 · nH2O | |
| 'Opal-AN' | SiO2 · nH2O | |
| 'Opal-C' | SiO2 · nH2O | |
| 'Opal-CT' | SiO2 · nH2O | |
| Quartz | SiO2 | Trig. 3 2 : P31 2 1 |
| 'Quartz-beta' | SiO2 | Hex. 6 2 2 : P64 2 2 |
| Seifertite | SiO2 | Orth. mmm (2/m 2/m 2/m) : Pbcn |
| Stishovite | SiO2 | Tet. 4/mmm (4/m 2/m 2/m) : P42/mnm |
| Tridymite | SiO2 | Tric. 1 |
| 'β-Cristobalite' | SiO2 | Iso. m3m (4/m 3 2/m) : Fd3m |
| 'β-Tridymite' | SiO2 |
Common Associates
Associations Based on Photo Data:
| 19 photos of Melanophlogite associated with 'Chalcedony' | SiO2 |
| 17 photos of Melanophlogite associated with Magnesite | MgCO3 |
| 12 photos of Melanophlogite associated with Native Sulphur | S8 |
| 7 photos of Melanophlogite associated with Cinnabar | HgS |
| 5 photos of Melanophlogite associated with Volkonskoite | Ca0.3(Cr,Mg,Fe)2((Si,Al)4O10)(OH)2 · 4H2O |
| 5 photos of Melanophlogite associated with Aragonite | CaCO3 |
| 4 photos of Melanophlogite associated with Celestine | SrSO4 |
| 4 photos of Melanophlogite associated with Dolomite | CaMg(CO3)2 |
| 2 photos of Melanophlogite associated with 'Bitumen' | |
| 2 photos of Melanophlogite associated with Goethite | Fe3+O(OH) |
Related Minerals - Strunz-mindat Grouping
| 4.DA. | Bosoite | SiO2 · nCxH2x+2 |
| 4.DA. | Chibaite | SiO2 · n(CH4, C2H6, C3H8, i-C4H10) (n = 3/17 (max)) |
| 4.DA. | 'Carbon Dioxide Ice' | CO2 |
| 4.DA.05 | Quartz | SiO2 |
| 4.DA.10 | Tridymite | SiO2 |
| 4.DA.10 | Opal | SiO2 · nH2O |
| 4.DA.15 | Cristobalite | SiO2 |
| 4.DA.20 | Mogánite | SiO2 |
| 4.DA.30 | Lechatelierite | SiO2 |
| 4.DA.35 | Coesite | SiO2 |
| 4.DA.35 | Xiexiandeite | SiO2 |
| 4.DA.40 | Stishovite | SiO2 |
| 4.DA.45 | 'Keatite' | SiO2 |
| 4.DA.50 | Seifertite | SiO2 |
| 4.DA.55 | 'Quartz-beta' | SiO2 |
Other Information
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 Melanophlogite
mindat.org URL:
https://www.mindat.org/min-2630.html
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References for Melanophlogite
Reference List:
Mallard, Ernest (1890) Note sur la mélanophlogite. Bulletin de la Société Française de Minéralogie, 13 (5). 180-182 doi:10.3406/bulmi.1890.2169
Friedel, Georges (1890) Sur la mélanophlogite. Bulletin de Minéralogie, 13 (9) 356-372 doi:10.3406/bulmi.1890.2196
Friedel, Georges (1891) Sur la Mélanophlogite. Bulletin de la Société Française de Minéralogie, 14 (3) 74-76 doi:10.3406/bulmi.1891.2214
Zambonini, F. (1906) Einige Beobachtungen über die optischen Eigenschaften des Melanophlogit. Zeitschrift für Kristallographie, 41 (1-6). 48-52 doi:10.1524/zkri.1906.41.1.48
Skinner, Brian J., Appleman, Daniel E. (1963) Melanophlogite, a cubic polymorph of silica. American Mineralogist, 48 (7-8) 854-867
Cooper, J. F., Jr., Dunning, G. E. (1972) Melanophlogite from Mount Hamilton, Santa Clara County, California. American Mineralogist, 57 (9-10). 1494-1504
Žák, Lubor (1972) A contribution to the crystal chemistry of melanophlogite. American Mineralogist, 57 (5-6). 779-796
Gies, H. (1983) Studies on clathrasils. III. Crystal structure of melanophlogite, a natural clathrate compound of silica. Zeitschrift für Kristallographie, 164 (3-4). 247-257 doi:10.1524/zkri.1983.164.3-4.247
Nakagawa, Takeshi, Kihara, Kuniaki, Harada, Kazuo (2001) The crystal structure of low melanophlogite. American Mineralogist, 86 (11) 1506-1512 doi:10.2138/am-2001-11-1219
NAKAGAWA, Takeshi, KIHARA, Kuniaki, FUJINAMI, Syuhei (2005) X-ray studies of structural changes in melanophlogite with varying temperature. Journal of Mineralogical and Petrological Sciences, 100 (6) 247-259 doi:10.2465/jmps.100.247
Tribaudino, M., Artoni, A., Mavris, C., Bersani, D., Lottici, P. P., Belletti, D. (2008) Single-crystal X-ray and Raman investigation on melanophlogite from Varano Marchesi (Parma, Italy) American Mineralogist, 93 (1) 88-94 doi:10.2138/am.2008.2528
Beard, A. D., Howard, K., Carmody, L., Jones, A. P. (2013) The origin of melanophlogite, a clathrate mineral, in natrocarbonatite lava at Oldoinyo Lengai, Tanzania. American Mineralogist, 98 (11) 1998-2006 doi:10.2138/am.2013.4264
Chukanov, N. V.; Vigasina, M.F.; Chervonyi, A. D.; Pekov, I. V. (2018) Vibrational spectroscopy and crystal chemical diversity of the natural clathrate — melanophlogite. Zapiski RMO (Proceedings of the Russian Mineralogical Society), 147 (2). 92-100 doi:10.30695/zrmo/2018.1472.06
Localities for Melanophlogite
Showing 51 localities.
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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.
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Fortullino, Rosignano Marittimo, Livorno Province, Tuscany, Italy