Fairchildite
A valid IMA mineral species - grandfathered
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About Fairchildite
John Gifford Fairchild
Formula:
K2Ca(CO3)2
Colour:
Colorless, light gray to bluish gray
Hardness:
2½
Specific Gravity:
2.45 (Calculated)
Crystal System:
Hexagonal
Name:
Named in honor of John Gifford Fairchild (28 May 1882, Monticello, New York, USA - 16 January 1965, Alexandria, Virginia, USA), analytical chemist, with the U.S. Geological Survey.
Co-Type Localities:
Dimorph of:
Unique Identifiers
Mindat ID:
1442
Long-form identifier:
mindat:1:1:1442:3
GUID
(UUID V4):
(UUID V4):
85432041-7bd9-476b-bdf5-e09569736d25
IMA Classification of Fairchildite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1947
Classification of Fairchildite
5.AC.20
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
C : Alkali and alkali-earth carbonates
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
C : Alkali and alkali-earth carbonates
14.3.3.1
14 : ANHYDROUS NORMAL CARBONATES
3 : A2B(XO3)2
14 : ANHYDROUS NORMAL CARBONATES
3 : A2B(XO3)2
11.1.16
11 : Carbonates
1 : Carbonates of the alkali metals and ammonium
11 : Carbonates
1 : Carbonates of the alkali metals and ammonium
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 |
|---|---|---|
| Fch | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Fairchildite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Fairchildite
Transparency:
Transparent
Colour:
Colorless, light gray to bluish gray
Hardness:
2½ on Mohs scale
Cleavage:
Distinct/Good
Good on {0001}.
Good on {0001}.
Density:
2.45 g/cm3 (Calculated)
Optical Data of Fairchildite
Type:
Uniaxial (-)
RI values:
nω = 1.533 nε = 1.498
Max Birefringence:
δ = 0.035
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
Chemistry of Fairchildite
Mindat Formula:
K2Ca(CO3)2
Elements listed:
Crystallography of Fairchildite
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P63/mmc
Cell Parameters:
a = 5.294(1) Å, c = 13.355(2) Å
Ratio:
a:c = 1 : 2.523
Unit Cell V:
324.15 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Tiny hexagonal plates flattened on {0001}. In dense stony aggregates.
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) |
|---|---|---|---|---|---|---|---|
| 0010845 | Fairchildite | Pertlik F (1981) Structural investigations of synthetic fairchildite, K2Ca(CO3)2 Zeitschrift fur Kristallographie 157 199-205 |  | 1981 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.19 Å | (very strong) |
| 2.641 Å | (strong) |
| 6 Å | ( |
| 64 Å | (medium) |
| 2.211 Å | (medium) |
| 2.154 Å | (medium) |
| 1.880 Å | (medium) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 56 : Slag and smelter minerals (see also #51 and #55) |
Geological Setting:
In clinkers in partly burned softwood trees such as hemlock and fir.
Type Occurrence of Fairchildite
Co-Type Localities:
Place of Conservation of Type Material:
National Museum of Natural History (Smithsonian Institution), Washington, D.C., USA, number 105675, 105676, 162622.
Geological Setting of Type Material:
Trees struck by lightning.
Reference:
Milton, C., Axelrod, J. (1947) Fused wood-ash stones: Fairchildite K2CO3·CaCO3, buetschliite 3K2CO3·2CaCO3·6H2O and calcite, CaCO3, their essential components. American Mineralogist: 32: 607-624.
Other Language Names for Fairchildite
Common Associates
Associated Minerals Based on Photo Data:
| 1 photo of Fairchildite associated with Bütschliite | K2Ca(CO3)2 |
Related Minerals - Strunz-mindat Grouping
| 5.AC.05 | Eitelite | Na2Mg(CO3)2 |
| 5.AC.10 | Nyerereite | Na2Ca(CO3)2 |
| 5.AC.10 | Zemkorite | Na2Ca(CO3)2 |
| 5.AC.15 | Bütschliite | K2Ca(CO3)2 |
| 5.AC.25 | Shortite | Na2Ca2(CO3)3 |
| 5.AC.30 | Burbankite | (Na,Ca)3(Sr,Ba,Ce)3(CO3)5 |
| 5.AC.30 | Calcioburbankite | Na3(Ca,REE,Sr)3(CO3)5 |
| 5.AC.30 | Khanneshite | (Na,Ca)3(Ba,Sr,Ce,Ca)3(CO3)5 |
| 5.AC.30 | Sanrománite | Na2CaPb3[CO3]5 |
| 5.AC.30 | Lishiite | (Ca2◻)Sr3(CO3)5 |
Other Information
Special Storage/
Display Requirements:
Display Requirements:
Slowly hygroscopic in air, altering to Bütschliite, and finally to calcite.
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 Fairchildite
mindat.org URL:
https://www.mindat.org/min-1442.html
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References for Fairchildite
Reference List:
Localities for Fairchildite
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.
Canada | |
| Kamenetsky et al. (2013) |
| Dawson et al. (1957) |
| Traill (1983) |
| Shang (2000) |
Chile | |
| Aguilera et al. (2016) |
Germany | |
| 58 (in German) +1 other reference |
| Schnorrer-Köhler et al. (1991) | |
Russia | |
| Zelenski et al. (2020) |
South Africa | |
| LM et al. (2009) |
| Giuliani et al. (2012) |
Syria | |
| Mahfoud et al. (1995) +1 other reference |
USA | |
| Milton (1944) +3 other references |
| Milton et al. (1947) | |
| - (n.d.) +1 other reference |
| Anthony et al. (2016) |
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Deseronto, Hastings County, Ontario, Canada