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Norbergite
A valid IMA mineral species - grandfathered
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About Norbergite
Formula:
Mg3(SiO4)F2
a n=1 (the most simple) member of the humite polysomatic series
Colour:
Orange-yellow, yellow, orange to brown.
Lustre:
Sub-Vitreous, Resinous, Waxy
Hardness:
6 - 6½
Specific Gravity:
3.177
Crystal System:
Orthorhombic
Member of:
Name:
Named in 1926 by Per Geijer after the type locality: The Östanmoss Mine, Norberg, Västmanland, Sweden.
Isostructural with:
Norbergite is a mineral in the humite group. It forms a polysomatic series with chondrodite, humite and clinohumite and it is often found with one or more of these minerals. To reflect the common structure of these minerals, the formula of the humite-group minerals can be expressed as M2n-1SinO2n•2M(OH,F)2O, where n can be 1, 2, 3 or 4 (Deer et al., 1997). The first part of the structural formula, M2n-1Sin, corresponds to the olivine-group formula, whereas the 2M(OH,F)2 layers (= "brucite" layers*) in the structure represents intermediate layers between the "olivine"-type layers. The norbergite formula corresponds to n = 1.
It is difficult to distinguish minerals in the humite group, as they largely occur in the same environments and localities. Their physical and optical appearances are also similar, as is the occurrence as rounded crystals or anhedral grains. A quantitative chemical analysis (electron microprobe) combined with structural analyses (XRD) seem to be required to identify individual humite-group species with absolute certainty.
Norbergite is F-dominant, and an hypothetical (OH)-dominant end member may not be stable in the common range of temperatures and pressures in the earth’s crust.
Norbergite is almost always found in metamorphic and metamorphosed limestone and dolomites and in the contact (calc-silicate rocks/skarns) between these and other rocks. It is often associated with different ores and other Mg-rich silicates such as phlogopite, tremolite and other Mg-rich minerals such as spinel and magnesite. Fluoborite is also an associate of norbergite at some localities. Norbergite normally occurs as isolated rounded grains, rarely as crude crystals. Well-formed crystals are very rare.
The best display specimens come from the Limecrest Quarry, New Jersey, USA.
Visit gemdat.org for gemological information about Norbergite.
It is difficult to distinguish minerals in the humite group, as they largely occur in the same environments and localities. Their physical and optical appearances are also similar, as is the occurrence as rounded crystals or anhedral grains. A quantitative chemical analysis (electron microprobe) combined with structural analyses (XRD) seem to be required to identify individual humite-group species with absolute certainty.
Norbergite is F-dominant, and an hypothetical (OH)-dominant end member may not be stable in the common range of temperatures and pressures in the earth’s crust.
Norbergite is almost always found in metamorphic and metamorphosed limestone and dolomites and in the contact (calc-silicate rocks/skarns) between these and other rocks. It is often associated with different ores and other Mg-rich silicates such as phlogopite, tremolite and other Mg-rich minerals such as spinel and magnesite. Fluoborite is also an associate of norbergite at some localities. Norbergite normally occurs as isolated rounded grains, rarely as crude crystals. Well-formed crystals are very rare.
The best display specimens come from the Limecrest Quarry, New Jersey, USA.
Visit gemdat.org for gemological information about Norbergite.Unique Identifiers
Mindat ID:
2925
Long-form identifier:
mindat:1:1:2925:0
IMA Classification of Norbergite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Mg3SiO4F2
First published:
1926
Classification of Norbergite
9.AF.40
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
52.3.2a.1
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
3 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] coordination only
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
3 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] coordination only
17.1.9
17 : Silicates Containing other Anions
1 : Silicates with fluoride (not containing Al)
17 : Silicates Containing other Anions
1 : Silicates with fluoride (not containing Al)
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Nrb | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Nrb | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Nrb | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
| Nrb | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Nrb | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Norbergite
Sub-Vitreous, Resinous, Waxy
Transparency:
Transparent, Translucent
Colour:
Orange-yellow, yellow, orange to brown.
Streak:
White
Hardness:
6 - 6½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
3.177 g/cm3 (Measured) 3.186 g/cm3 (Calculated)
Optical Data of Norbergite
Type:
Biaxial (+)
RI values:
nα = 1.563 - 1.567 nβ = 1.567 - 1.579 nγ = 1.590 - 1.593
2V:
Measured: 44° to 50°
Birefringence:
0.027
Max. Birefringence:
δ = 0.026 - 0.027
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 µm 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 µm 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:
Moderate (positive)
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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r>v, slight to strong
Chemistry of Norbergite
Mindat Formula:
Mg3(SiO4)F2
a n=1 (the most simple) member of the humite polysomatic series
a n=1 (the most simple) member of the humite polysomatic series
Element Weights:
Elements listed:
Common Impurities:
Ti,Al,Fe,Mn,Zn,Ca,H2O
Crystallography of Norbergite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 8.747(6) Å, b = 4.710(4) Å, c = 10.271(8) Å
Ratio:
a:b:c = 1.857 : 1 : 2.181
Unit Cell V:
423.15 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space-group Pmcn (non-standard setting); data for synthetic material
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) |
|---|---|---|---|---|---|---|---|
| 0005536 | Norbergite | Camara F (1997) New data on the structure of norbergite: location of hydrogen by X-ray diffraction The Canadian Mineralogist 35 1523-1530 |  | 1997 | 0 | 293 | |
| 0005535 | Norbergite | Camara F (1997) New data on the structure of norbergite: location of hydrogen by X-ray diffraction The Canadian Mineralogist 35 1523-1530 | | 1997 | 0 | 293 | |
| 0000190 | Norbergite | Gibbs G V, Ribbe P H (1969) The crystal structures of the humite minerals: I. Norbergite American Mineralogist 54 376-390 | | 1969 | 0 | 293 | |
| 0017920 | Norbergite | Taylor W, West J (1929) The Structure of Norbergite _cod_database_code 1011009 Zeitschrift fur Kristallographie 70 461-474 | 1929 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.14 Å | (18) |
| 4.43 Å | (10) |
| 4.371 Å | (30) |
| 4.283 Å | (12) |
| 4.149 Å | (20) |
| 3.327 Å | (20) |
| 3.227 Å | (25) |
| 3.058 Å | (100) |
| 2.771 Å | (14) |
| 2.716 Å | (12) |
| 2.639 Å | (75) |
| 2.466 Å | (16) |
| 2.408 Å | (35) |
| 2.337 Å | (35) |
| 2.296 Å | (16) |
| 2.255 Å | (70) |
| 2.230 Å | (80) |
| 2.214 Å | (8) |
| 2.184 Å | (8) |
| 2.032 Å | (10) |
| 2.0068 Å | (6) |
| 1.9442 Å | (14) |
| 1.9243 Å | (6) |
| 1.9201 Å | (6) |
| 1.8472 Å | (8) |
| 1.8408 Å | (10) |
| 1.7733 Å | (4) |
| 1.7357 Å | (30) |
| 1.7241 Å | (50) |
| 1.7125 Å | (6) |
| 1.7022 Å | (14) |
| 1.6529 Å | (10) |
| 1.6160 Å | (8) |
| 1.6125 Å | (10) |
| 1.6004 Å | (10) |
| 1.5938 Å | (10) |
| 1.5808 Å | (6) |
| 1.5678 Å | (4) |
| 1.5518 Å | (2) |
| 1.4763 Å | (45) |
Comments:
ICDD 11-686, For synthetic material
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 7 : Ultramafic igneous rocks | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 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 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Geological Setting:
High grade carbonate rocks with a high Mg/Si ratio and F content.
Type Occurrence of Norbergite
Synonyms of Norbergite
Other Language Names for Norbergite
Varieties of Norbergite
| Maclureite | Maclureite variety of "chondrodite" is apparently what is now considered to be brownish yellow to orange norbergite. "[']It occurs occasionally in small four-sided prisms, (of a paler colour than the amorphous masses,) with rhombic bases of 124° and 56°... |
Relationship of Norbergite to other Species
Member of:
Other Members of Humite Subgroup:
| Chondrodite | Mg5(SiO4)2F2 | Mon. 2/m : P21/c |
| Clinohumite | Mg9(SiO4)4F2 | Mon. 2/m : P21/c |
| Humite | Mg7(SiO4)3F2 | Orth. mmm(2/m2/m2/m) : Pnma |
| Hydroxylchondrodite | Mg5(SiO4)2(OH)2 | Mon. 2/m : P21/c |
| Hydroxylclinohumite | Mg9(SiO4)4(OH)2 | Mon. 2/m : P21/c |
| 'Unnamed (OH-analogue of humite)' | Mg7(SiO4)3(OH)2 | Orth. |
Common Associates
Associations Based on Photo Data:
| 113 photos of Norbergite associated with Calcite | CaCO3 |
| 70 photos of Norbergite associated with Graphite | C |
| 42 photos of Norbergite associated with Diopside | CaMgSi2O6 |
| 28 photos of Norbergite associated with Spinel | MgAl2O4 |
| 10 photos of Norbergite associated with Phlogopite | KMg3(AlSi3O10)(OH)2 |
| 9 photos of Norbergite associated with Pyrite | FeS2 |
| 7 photos of Norbergite associated with Fluorophlogopite | KMg3(Si3Al)O10F2 |
| 6 photos of Norbergite associated with Fluoborite | Mg3(BO3)(F,OH)3 |
| 5 photos of Norbergite associated with 'Marble' | |
| 4 photos of Norbergite associated with Pyrrhotite | Fe1-xS |
Related Minerals - Strunz-mindat Grouping
| 9.AF. | Chegemite | Ca7(SiO4)3(OH)2 |
| 9.AF. | Jingwenite-(Y) | YAlV4+(SiO4)O2(OH)2 |
| 9.AF. | Barwoodite | Mn2+6Nb5+(SiO4)2O3(OH)3 |
| 9.AF.05 | Sillimanite | Al2(SiO4)O |
| 9.AF.05 | 'Xenolite' | Al10Si8O31 |
| 9.AF.10 | Kanonaite | Mn3+Al(SiO4)O |
| 9.AF.10 | Andalusite | Al2(SiO4)O |
| 9.AF.15 | Kyanite | Al2(SiO4)O |
| 9.AF.20 | Krieselite | Al2(GeO4)F2 |
| 9.AF.20 | Mullite | Al4+2xSi2-2xO10-x |
| 9.AF.23 | Boromullite | Al9BSi2O19 |
| 9.AF.25 | Yoderite | Mg(Al,Fe3+)3(SiO4)2O(OH) |
| 9.AF.30 | Zincostaurolite | Zn2Al9Si4O23(OH) |
| 9.AF.30 | Staurolite | Fe2+2Al9Si4O23(OH) |
| 9.AF.30 | Magnesiostaurolite | Mg(Mg,Li)3(Al,Mg)18Si8O44(OH)4 |
| 9.AF.35 | Topaz | Al2(SiO4)(F,OH)2 |
| 9.AF.45 | Chondrodite | Mg5(SiO4)2F2 |
| 9.AF.45 | Kumtyubeite | Ca5(SiO4)2F2 |
| 9.AF.45 | Reinhardbraunsite | Ca5(SiO4)2(OH,F)2 |
| 9.AF.45 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 |
| 9.AF.45 | Alleghanyite | Mn2+5(SiO4)2(OH)2 |
| 9.AF.50 | 'Unnamed (Ca-analogue of Humite)' | Ca7(SiO4)4F2 |
| 9.AF.50 | Humite | Mg7(SiO4)3F2 |
| 9.AF.50 | Manganhumite | Mn2+7(SiO4)3(OH)2 |
| 9.AF.50 | 'Unnamed (OH-analogue of humite)' | Mg7(SiO4)3(OH)2 |
| 9.AF.50 | Fluorchegemite | Ca7(SiO4)3F2 |
| 9.AF.55 | Hydroxylclinohumite | Mg9(SiO4)4(OH)2 |
| 9.AF.55 | Clinohumite | Mg9(SiO4)4F2 |
| 9.AF.55 | Sonolite | Mn2+9(SiO4)4(OH)2 |
| 9.AF.60 | Leucophoenicite | Mn2+7(SiO4)3(OH)2 |
| 9.AF.65 | Ribbeite | Mn2+5(SiO4)2(OH)2 |
| 9.AF.70 | Jerrygibbsite | Mn2+9(SiO4)4(OH)2 |
| 9.AF.75 | Franciscanite | Mn2+6(V5+,◻)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Scorticoite | Mn6(Sb,◻)Σ2(SiO4)2O3(OH)3 |
| 9.AF.75 | Welinite | Mn2+6(W6+,Mg)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Örebroite | Mn2+3(Sb5+,Fe3+)(SiO4)(O,OH)3 |
| 9.AF.80 | Ellenbergerite | Mg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10 |
| 9.AF.85 | Magnesiochloritoid | MgAl2O(SiO4)(OH)2 |
| 9.AF.85 | Ottrélite | Mn2+Al2O(SiO4)(OH)2 |
| 9.AF.85 | Chloritoid | Fe2+Al2O(SiO4)(OH)2 |
| 9.AF.90 | Olmiite | CaMn2+[SiO3(OH)](OH) |
| 9.AF.90 | Poldervaartite | CaCa[SiO3(OH)](OH) |
| 9.AF.95 | Pilawite-(Y) | Ca2Y2Al4(SiO4)4O2(OH)2 |
Fluorescence of Norbergite
May fluoresce bright to weak yellow to pale yellow in SW; less bright in mid-wave UV, not fluorescent in long wave.
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 Norbergite
mindat.org URL:
https://www.mindat.org/min-2925.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Norbergite
Reference List:
Geijer, Per (1926) Norbergite and Fluoborite, two new minerals from the Norberg mining district. Geologiska Föreningen i Stockholm Förhandlingar, 48 (1). 84-85 doi:10.1080/11035892609445642
Strunz, H. (1938) Isotypie zwischen Skorodit und Norbergit Fe[AsO4/(Η2Ο)2] und Mg3[SiO4/(OH,F)2]. Zeitschrift für Kristallographie, Mineralogie und Petrographie, 99 (1-6). 513-514 doi:10.1524/zkri.1938.99.1.513
Ribbe, P. H., Gibbs, G. V., Jones, Norris W. (1968) Cation and anion substitutions in the humite minerals. Mineralogical Magazine and Journal of the Mineralogical Society, 36 (283) 966-975 doi:10.1180/minmag.1968.283.036.08
Gibbs, G. V., Ribbe, P. H. (1969) The crystal structures of the humite minerals: I. Norbergite. American Mineralogist, 54 (3-4) 376-390
Jones, Norris W., Ribbe, P. H., Gibbs, G. V. (1969) Crystal chemistry of the humite minerals. American Mineralogist, 54 (3-4) 391-411
Ribbe, P. H., Gibbs, G. V. (1971) Crystal structures of the humite minerals: III. Mg /Fe ordering in humite and its relation to other ferromagnesian silicates. American Mineralogist, 56 (5-6) 1155-1173
Ribbe, Paul H. (1979) Titanium, fluorine, and hydroxyl in the humite minerals. American Mineralogist, 64 (9-10) 1027-1035
Localities for Norbergite
Showing 49 localities.
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.
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Franklin Quarry, Franklin, Sussex County, New Jersey, USA