Afwillite
A valid IMA mineral species - grandfathered
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About Afwillite
Formula:
Ca3(HSiO4)2 · 2H2O
Colour:
Colourless, white; rarely blue
Lustre:
Vitreous
Hardness:
3 - 4
Specific Gravity:
2.630
Crystal System:
Monoclinic
Name:
Named in 1925 by John Parry and Frederick Eugene Wright in honor of Alpheus Fuller Williams [June 21, 1874 Oakland Alameda County California, USA - January 6, 1953 Cape Town, Western Cape, South Africa] of the De Beers Consolidated Mines of South Africa.
This page provides mineralogical data about Afwillite.
Unique Identifiers
IMA Classification of Afwillite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca3[SiO4][SiO2(OH)2] · 2H2O
First published:
1925
Classification of Afwillite
9.AG.75
9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
52.4.7.1
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
4 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
4 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
14.5.11
14 : Silicates not Containing Aluminum
5 : Silicates of Ca
14 : Silicates not Containing Aluminum
5 : Silicates of Ca
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 |
---|---|---|
Afw | 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 Afwillite
Vitreous
Transparency:
Transparent
Colour:
Colourless, white; rarely blue
Streak:
White
Hardness:
3 - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {101}, good on {100}
Perfect on {101}, good on {100}
Fracture:
Conchoidal
Density:
2.630 g/cm3 (Measured) 2.643(5) g/cm3 (Calculated)
Optical Data of Afwillite
Type:
Biaxial (+)
RI values:
nα = 1.617 nβ = 1.620 nγ = 1.634
2V:
Measured: 50° to 56°
Max Birefringence:
δ = 0.017
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:
Moderate
Dispersion:
r < v
Optical Extinction:
Y = b; X ∧ c = 31.2°.
Chemistry of Afwillite
Mindat Formula:
Ca3(HSiO4)2 · 2H2O
Elements listed:
Common Impurities:
Al,Fe,Mg,F
Crystallography of Afwillite
Crystal System:
Monoclinic
Class (H-M):
m - Domatic
Space Group:
Bb
Cell Parameters:
a = 16.278(1) Å, b = 5.6321(4) Å, c = 13.236(1) Å
β = 134.9°
β = 134.9°
Ratio:
a:b:c = 2.89 : 1 : 2.35
Unit Cell V:
859.55 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals are prismatic, tabular, radial fibrous spherulites, massive.
Known forms include {001}, {100}, {110}, {310}, {011}, {045}, {013}, {101}, {101}, {302}, {112}, {121}, {211}, {213}, {312}.
Known forms include {001}, {100}, {110}, {310}, {011}, {045}, {013}, {101}, {101}, {302}, {112}, {121}, {211}, {213}, {312}.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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2x2x2 | 3x3x3 | 4x4x4
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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) |
---|---|---|---|---|---|---|---|
0009147 | Afwillite | Megaw H D (1952) The structure of afwillite, Ca3(SiO3OH)2*2H2O Acta Crystallographica 5 477-491 | 1952 | Scawt Hill, Northern Ireland | 0 | 293 | |
0009551 | Afwillite | Malik K M A, Jeffery J W (1976) A re-investigation of the structure of afwillite Acta Crystallographica B32 475-480 | 1976 | 0 | 293 | ||
0012415 | Afwillite | Rastsvetaeva R K, Chukanov N V, Zadov A E (2009) Refined structure of afwillite from the northern Baikal region Crystallography Reports 54 418-422 | 2009 | Yoko Dovyrensky massif, northern Baikal region, Russia | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
2.83 Å | (100) |
6.61 Å | (90) |
3.18 Å | (90) |
2.73 Å | (90) |
3.28 Å | (70) |
2.15 Å | (70) |
2.34 Å | (60) |
Comments:
Dutoitspan mine, Kimberley, South Africa. Data from Switzer and Bailey (1953).
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
High-𝑇 alteration and/or metamorphism | |
31 : Thermally altered carbonate, phosphate, and iron formations | |
Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
Geological Setting:
Contact metamorphism of limestones.
Type Occurrence of Afwillite
General Appearance of Type Material:
Large crystals (11 x 4 x 1.5 cm) composed of sub-parallel individuals.
Place of Conservation of Type Material:
The Natural History Museum, London, England, number 1925,80 (cotype).
National Museum of Natural History, Washington, D.C., USA, number 95237 (type).
National Museum of Natural History, Washington, D.C., USA, number 95237 (type).
Geological Setting of Type Material:
In a large dolerite inclusion in kimberlite.
Associated Minerals at Type Locality:
Reference:
Parry, J., Wright, F.E. (1925) Afwillite, a new hydrous calcium silicate, from Dutoitspan mine, Kimberley, South Africa. Mineralogical Magazine: 20: 277-285.
Other Language Names for Afwillite
Common Associates
Associated Minerals Based on Photo Data:
20 photos of Afwillite associated with Ettringite | Ca6Al2(SO4)3(OH)12 · 26H2O |
14 photos of Afwillite associated with Calcite | CaCO3 |
12 photos of Afwillite associated with Gypsum | CaSO4 · 2H2O |
5 photos of Afwillite associated with Hydrocalumite | Ca4Al2(OH)12(Cl,CO3,OH)2 · 4H2O |
5 photos of Afwillite associated with Monticellite | CaMgSiO4 |
5 photos of Afwillite associated with Vesuvianite | Ca19Fe3+Al4(Al6Mg2)(◻4)◻[Si2O7]4[(SiO4)10]O(OH)9 |
4 photos of Afwillite associated with Brucite | Mg(OH)2 |
3 photos of Afwillite associated with Thaumasite | Ca3(SO4)[Si(OH)6](CO3) · 12H2O |
3 photos of Afwillite associated with Portlandite | Ca(OH)2 |
3 photos of Afwillite associated with Vaterite | CaCO3 |
Related Minerals - Strunz-mindat Grouping
9.AG. | Ivanyukite-Na-T | Na2Ti4(SiO4)3(OH)O3 · 7H2O |
9.AG. | Ivanyukite-Na-C | Na2Ti4(SiO4)3(OH)2O2 · 6H2O |
9.AG. | Edgrewite | Ca9(SiO4)4F2 |
9.AG. | Aluminotaipingite-(CeCa) | (Ce6Ca3)◻Al(SiO4)3[SiO3(OH)]4F3 |
9.AG.02 | Gatedalite | ZrMn2+2Mn3+4SiO12 |
9.AG.2 | Skogbyite | Zr(Mg2Mn3+4)SiO12 |
9.AG.05 | Abswurmbachite | CuMn3+6(SiO4)O8 |
9.AG.05 | Braunite | Mn2+Mn3+6(SiO4)O8 |
9.AG.05 | Neltnerite | CaMn3+6(SiO4)O8 |
9.AG.05 | Braunite-II | CaMn3+14(SiO4)O20 |
9.AG.10 | Långbanite | Mn2+4Mn3+9Sb5+O16(SiO4)2 |
9.AG.12 | Taipingite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3[SiO3(OH)]4F3 |
9.AG.15 | Malayaite | CaSn(SiO4)O |
9.AG.15 | Titanite | CaTi(SiO4)O |
9.AG.15 | Vanadomalayaite | CaV4+(SiO4)O |
9.AG.15 | Natrotitanite | (Na0.5Y0.5)Ti(SiO4)O |
9.AG.15 | Żabińskiite | Ca[Al0.5(Ta,Nb)0.5)](SiO4)O |
9.AG.20 | Cerite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3(SiO3OH)4(OH)3 |
9.AG.20 | Ferricerite-(LaCa) | (La6Ca3)◻Fe3+(SiO4)3(SiO3OH)4(OH)3 |
9.AG.20 | Aluminocerite-(CeCa) | (Ce6Ca3)◻Al(SiO4)3[SiO3(OH)]4(OH)3 |
9.AG.20 | Nipeiite-(Ce) | Ce9Fe3+(SiO4)6[SiO3(OH)](OH)3 |
9.AG.25 | Trimounsite-(Y) | Y2Ti2(SiO4)O5 |
9.AG.25 | Yftisite-(Y) | (Y,Dy,Er)4(Ti,Sn)(SiO4)2O(F,OH)6 |
9.AG.25 | Mieite-(Y) | Y4Ti(SiO4)2O[F,(OH)]6 |
9.AG.30 | Sitinakite | KNa2Ti4(SiO4)2O5(OH) · 4H2O |
9.AG.35 | Kittatinnyite | Ca2Mn2Mn(SiO4)2(OH)4 · 9H2O |
9.AG.40a | Natisite | Na2Ti(SiO4)O |
9.AG.40b | Paranatisite | Na2Ti(SiO4)O |
9.AG.45 | Törnebohmite-(Ce) | Ce2Al(SiO4)2(OH) |
9.AG.45 | Törnebohmite-(La) | La2Al(SiO4)2(OH) |
9.AG.50 | Kuliokite-(Y) | Y4Al(SiO4)2(OH)2F5 |
9.AG.50 | Ivanyukite-Na | Na2Ti4(SiO4)3(OH)2O2 · 6H2O |
9.AG.50 | Ivanyukite-K | K2Ti4(SiO4)3(OH)2O2 · 9H2O |
9.AG.50 | Ivanyukite-Cu | CuTi4(SiO4)3(OH)2O2 · 7H2O |
9.AG.50 | Hydroxyledgrewite | Ca9(SiO4)4(OH)2 |
9.AG.52 | Ulfanderssonite-(Ce) | (Ce15Ca)Σ16Mg2(SiO4)10(SiO3OH)(OH,F)5Cl3 |
9.AG.55 | Chantalite | CaAl2(SiO4)(OH)4 |
9.AG.60 | Mozartite | CaMn3+(SiO4)(OH) |
9.AG.60 | Vuagnatite | CaAl(SiO4)(OH) |
9.AG.65 | Hatrurite | Ca3(SiO4)O |
9.AG.70 | Jasmundite | Ca11(SiO4)4O2S |
9.AG.80 | Bultfonteinite | Ca2(HSiO4)F · H2O |
9.AG.85 | Zoltaiite | BaV4+2V3+12(SiO4)2O19 |
9.AG.90 | Tranquillityite | (Fe2+,Ca)8(Zr,Y)2Ti3(SiO4)3O12 |
Other Information
Electrical:
Piezoelectric
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 Afwillite
mindat.org URL:
https://www.mindat.org/min-42.html
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References for Afwillite
Reference List:
Kusachi, Isao, Henmi, Chiyoko, Henmi, Kitinosuke (1989) Afwillite and jennite from Fuka, Okayama Prefecture, Japan. Mineralogical Journal, 14 (7) 279-292 doi:10.2465/minerj.14.279
Localities for Afwillite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Austria | |
| Walter Trattner collection |
France | |
| Grünhagen H and Mergoil J (1963) |
Germany | |
| Pöllmann (1991) |
| Mineralogical Society of America - ... |
| Skrzyńska et al. (2023) |
| Blass |
| Hentschel (1987) |
in the collection of Christof Schäfer | |
| Hentschel (1983) |
| Schüller et al. (1986) |
| Blass et al. (2006) |
Ireland | |
| Nawaz (1974) +1 other reference |
Israel | |
| Galuskin et al. (2015) |
Britvin et al. (2021) +1 other reference | |
Krzątała et al. (2023) | |
Sharygin +7 other references | |
| GROSS et al. (1967) |
Italy | |
| Caponera et al. (2007) |
| Fiori et al. (2002) +2 other references |
| Passaglia et al. (1982) |
| Stoppa F. et al. (2010) |
| 50 +2 other references |
Japan | |
| Yamada (2004) |
| Kusachi et al. (1989) |
| Kusachi et al. (1989) +1 other reference |
Jordan | |
| Pitty et al. (2010) |
| Fleurance et al. (2013) |
| Vapnik et al. (2019) |
| Khoury et al. (1985) |
Middle East | |
Gross (1977) | |
New Zealand | |
| Railton et al. (1990) |
Palestine | |
| Galuskin et al. (2015) |
Krüger +5 other references | |
Romania | |
| Szakáll |
Szakáll et al. (2010) | |
| Marincea et al. (2011) |
| Marincea et al. (2013) |
Russia | |
| American Mineralogist |
| Bailau +1 other reference |
| Galuskina et al. (2015) |
Galuskin et al. (2011) | |
| |
South Africa (TL) | |
| Parry et al. (1925) +1 other reference |
| Von Bezing et al. (1991) |
Cairncross et al. (1995) | |
Cairncross et al. (1995) | |
UK | |
| Nawaz (1977) |
Tilley (1930) +3 other references | |
USA | |
| Switzer et al. (1953) +2 other references |
| Sherwood et al. (1998) |
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Crestmore quarries, Crestmore, Jurupa Valley, Riverside County, California, USA