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Mellite
A valid IMA mineral species - grandfathered
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About Mellite
Formula:
Al2[C6(COO)6] · 16H2O
Colour:
Honey to wax yellow, brown to reddish, gray, seldom white; colourless to pale yellow in transmitted light.
Lustre:
Vitreous, Resinous, Greasy
Hardness:
2 - 2½
Specific Gravity:
1.64
Crystal System:
Tetragonal
Name:
From the Greek ÎŒÎλÎč ("meli") = honey, in allusion to the colour.
Type Locality:
Aluminium mellitate (benzene hexacarboxylate) hydrate.
A rare secondary mineral in lignite deposits.
Visit gemdat.org for gemological information about Mellite.
A rare secondary mineral in lignite deposits.
Visit gemdat.org for gemological information about Mellite.Unique Identifiers
Mindat ID:
2638
Long-form identifier:
mindat:1:1:2638:9
Similar Names
IMA Classification of Mellite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Al2C6(COO)6·16H2O
Classification of Mellite
10.AC.05
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
C : Benzine Salts
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
C : Benzine Salts
Dana 7th ed.:
50.2.1.1
50.2.1.1
50 : ORGANIC COMPOUNDS
2 : Mellitates, Citrates, Cyanates, Acetates and Formates
50 : ORGANIC COMPOUNDS
2 : Mellitates, Citrates, Cyanates, Acetates and Formates
31.3.1
31 : Oxalates, Citrates, Mellitates and Acetates
3 : Mellitates
31 : Oxalates, Citrates, Mellitates and Acetates
3 : Mellitates
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mel | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Mellite
Vitreous, Resinous, Greasy
Transparency:
Transparent, Translucent
Colour:
Honey to wax yellow, brown to reddish, gray, seldom white; colourless to pale yellow in transmitted light.
Streak:
White
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Sectile
Cleavage:
Poor/Indistinct
On {023}, indistinct
On {023}, indistinct
Fracture:
Conchoidal
Density:
1.64 g/cm3 (Measured) 1.65 g/cm3 (Calculated)
Optical Data of Mellite
Type:
Uniaxial (-)
RI values:
nω = 1.539 nε = 1.511
Max. Birefringence:
δ = 0.028
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 ”m thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 ”m thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
None to Very Low
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Weak
Comments:
O = yellowish brown
E = Yellow
E = Yellow
Comments:
May be anomalously biaxial.
2V (measured)= Small.
2V (measured)= Small.
Chemistry of Mellite
Mindat Formula:
Al2[C6(COO)6] · 16H2O
Element Weights:
Elements listed:
Crystallography of Mellite
Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
I41/acd
Cell Parameters:
a = 15.53 Å, c = 23.19 Å
Ratio:
a:c = 1 : 1.493
Unit Cell V:
5,592.99 Ă
Âł (Calculated from Unit Cell)
Z:
8
Morphology:
Crystals dipyramidal {023}, also prismatic, elongated [001], modified by {001},{010}, and {113}; also occurs as nodules and coatings; fine-grained massive.
Crystallographic forms of Mellite
Crystal Atlas:
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Mellite no.2 - {101} - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
www.smorf.nl.
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Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0013713 | Mellite | Robl C, Kuhs W F (1991) A neutron diffraction study on hydrogen bonding in the mineral mellite (Al2[C6(COO)6]*16H2O) at 15 K Journal of Solid State Chemistry 92 101-109 | 1991 | Tatabanya, Hungary | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.99 Ă | (100) |
| 5.80 Ă | (55) |
| 5.16 Ă | (40) |
| 4.23 Ă | (70) |
| 3.46 Ă | (30) |
| 3.39 Ă | (30) |
| 2.985 Ă | (25) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 1: Primary nebular phases | 4.567-4.561 |
| 3 : Solar nebular condensates (CAIs, AOAs, URIs) | >4.565 |
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Stage 3a: Earthâs earliest Hadean crust | >4.50 |
| 8 : Mafic igneous rocks | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks | |
| 36 : Carbonatites, kimberlites, and related igneous rocks | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
Type Occurrence of Mellite
Synonyms of Mellite
Other Language Names for Mellite
Common Associates
Associations Based on Photo Data:
| 3 photos of Mellite associated with Calcite | CaCO3 |
| 2 photos of Mellite associated with Gypsum | CaSO4 · 2H2O |
| 1 photo of Mellite associated with Perovskite | CaTiO3 |
| 1 photo of Mellite associated with Pyroxene Group | ADSi2O6 |
| 1 photo of Mellite associated with Humboldtine | Fe2+(C2O4) · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 10.AC.10 | Earlandite | Ca3[CH2(COO)-CHOH(COO)-CH2(COO)]2 · 4H2O |
| 10.AC.15 | Pigotite | Al4C6H5O10 · 13H2O (?) |
Fluorescence of Mellite
Pale yellow to blue (LW & SW UV).
Other Information
Electrical:
Pyroelectric
Notes:
Insoluble in water and alcohol but soluble in HNO3.
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 Mellite
mindat.org URL:
https://www.mindat.org/min-2638.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Mellite
Reference List:
Richard Kirwan (1794) Elements of Mineralogy - second edition Vol. 1. P. Elmsly, The Strand.p.68 - as Mellilite
Klaproth, M. H. (1802) LXXXIV. Untersuchung des Honigsteins. In BeitrÀge zur chemischen Kenntniss der Mineralkörper Vol. 3. Rottmann. p.114-134.
Barth, Tom F. W., Ksanda, C. J. (1933) Crystallographic data on mellite. American Mineralogist, 18 (1) 8-13
Jobbins, E. A., Sergeant, G. A., Young, B. R. (1965) X-ray and other data for mellite. Mineralogical Magazine and Journal of the Mineralogical Society, 35 (271) 542-544 doi:10.1180/minmag.1965.035.271.10
Giacovazzo, C., Menchetti, S., Scordari, F. (1973) The crystal structure of mellite. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 29 (1) 26-31 doi:10.1107/s0567740873001925
Localities for Mellite
Showing 15 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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.
Australia | |
| Parbhakar-Fox et al. (2019) |
Austria | |
| Niedermayr et al. (1995) |
Czech Republic | |
| Duda |
| Palache et al. (1951) |
| Palache et al. (1951) |
| Petr Fuchs specimen |
France | |
| Palache et al. (1951) |
Germany | |
| Palache et al. (1951) |
| |
| D.L.G. Karsten (1789) +1 other reference |
Greenland | |
| Brooks (2011) |
Hungary | |
| Annual report of the Hungarian ... +1 other reference |
Italy | |
| Garavelli et al. (1974) |
| Marco Bonifazi find & collection +1 other reference |
Russia | |
| Palache et al. (1951) +1 other reference |
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CsordakĂști Mine, Bicske-CsordakĂșt, Bicskei District, FejĂ©r County, Hungary