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Wollastonite-1A
A structural variant of Wollastonite
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About Wollastonite-1A
William Hyde Wollaston
Formula:
CaSiO3
Colour:
white
Lustre:
Vitreous
Hardness:
5
Specific Gravity:
2.922
Crystal System:
Triclinic
Name:
Named in honour of William Hyde Wollaston (6 August 1766, East Dereham, Norfolk, England, UK - 22 December 1828, London, England, UK), English chemist and mineralogist who discovered palladium (1804) and rhodium (1809) and invented the reflecting goniometer (1809) and the camera lucida (1812).
A polytype of Wollastonite
Originally described from Dognecea (Dognaczka; Dognacska), Banat, Caras-Severin Co., Romania.
Originally described from Dognecea (Dognaczka; Dognacska), Banat, Caras-Severin Co., Romania.
Unique Identifiers
Mindat ID:
7369
Long-form identifier:
mindat:1:1:7369:7
Similar Names
| Wollastonite-3T | A synonym of 'Wollastonite-3A' |
| Wollastonite-4T | A synonym of 'Wollastonite-4A' |
| Wollastonite-5T | A synonym of 'Wollastonite-5A' |
| Wollastonite-7T | A synonym of 'Wollastonite-7A' |
Classification of Wollastonite-1A
9.DG.05
9 : SILICATES (Germanates)
D : Inosilicates
G : Inosilicates with 3-periodic single and multiple chains
9 : SILICATES (Germanates)
D : Inosilicates
G : Inosilicates with 3-periodic single and multiple chains
65.2.1.1a
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
2 : Single-Width Unbranched Chains, W=1 with chains P=3
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
2 : Single-Width Unbranched Chains, W=1 with chains P=3
Physical Properties of Wollastonite-1A
Vitreous
Colour:
White
Hardness:
5 on Mohs scale
Cleavage:
Very Good
The perfect cleavage on {100} can be easily observed, as well as the good cleavages on {001} and {102}.
The perfect cleavage on {100} can be easily observed, as well as the good cleavages on {001} and {102}.
Density:
2.922(2) g/cm3 (Measured) 2.916 g/cm3 (Calculated)
Optical Data of Wollastonite-1A
Type:
Biaxial (-)
RI values:
nα = 1.615 - 1.646 nβ = 1.627 - 1.659 nγ = 1.629 - 1.662
2V:
Measured: 40° , Calculated: 44° to 50°
Max. Birefringence:
δ = 0.014 - 0.016
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:
High (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 distinct
Chemistry of Wollastonite-1A
Mindat Formula:
CaSiO3
Element Weights:
Elements listed:
Crystallography of Wollastonite-1A
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 7.9233(3) Å, b = 7.3203(3) Å, c = 7.0651(3) Å
α = 90.053°, β = 95.208(3)°, γ = 103.384(3)°
α = 90.053°, β = 95.208(3)°, γ = 103.384(3)°
Ratio:
a:b:c = 1.082 : 1 : 0.965
Unit Cell V:
396.91 ų (Calculated from Unit Cell)
Z:
6
Morphology:
radial or sheaf-like aggregates composed of individual crystals up to 30 mm long and 1 mm wide. Individual crystals are elongated along the [010] axis.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.314 Å | (100) |
| 3.83 Å | (84) |
| 3.51 Å | (77) |
| 3.086 Å | (58) |
| 2.302 Å | (52) |
| 2.556 Å | (44) |
| 1.759 Å | (35) |
Reference:
Synonyms of Wollastonite-1A
Other Language Names for Wollastonite-1A
German:Wollastonit-1A
Russian:Волластонит-1T
Common Associates
Associations Based on Photo Data:
| 1 photo of Wollastonite-1A associated with Vesuvianite | Ca19Fe3+Al4(Al6Mg2)(◻4)◻[Si2O7]4[(SiO4)10]O(OH)9 |
Related Minerals - Strunz-mindat Grouping
| 9.DG. | Barrydawsonite-(Y) | Na1.5Y0.5CaSi3O8(OH) |
| 9.DG. | Paratobermorite | Ca5AlSi5O16(OH) · 5H2O |
| 9.DG. | Calcinaksite | KNaCa(Si4O10) · H2O |
| 9.DG. | Alvesite | NaKZrSi6O15 · 2H2O |
| 9.DG.02 | Steedeite | NaMn2[Si3BO9](OH)2 |
| 9.DG.02 | Nolzeite | NaMn2[Si3BO9](OH)2 · 2H2O |
| 9.DG.05 | Murakamiite | LiCa2Si3O8(OH) |
| 9.DG.05 | Serandite | NaMn2+2Si3O8(OH) |
| 9.DG.05 | Bustamite | CaMn2+(Si2O6) |
| 9.DG.05 | Pectolite | NaCa2Si3O8(OH) |
| 9.DG.05 | Tanohataite | LiMn2Si3O8(OH) |
| 9.DG.05 | Dalnegorskite | Ca5Mn2+(Si3O9)2 |
| 9.DG.05 | Wollastonite | Ca3(Si3O9) |
| 9.DG.05 | Ferrobustamite | CaFe2+(Si2O6) |
| 9.DG.05 | Schizolite | NaCaMnSi3O8(OH) |
| 9.DG.07 | Cascandite | CaScSi3O8(OH) |
| 9.DG.08 | Plombièrite | Ca5Si6O16(OH)2 · 7H2O |
| 9.DG.10 | Clinotobermorite | Ca5Si6O17 · 5H2O |
| 9.DG.10 | Riversideite | Ca5Si6O16(OH)2 · 2H2O |
| 9.DG.10 | Tobermorite | Ca5Si6O17 · 5H2O |
| 9.DG.12 | Jusite | Na2Ca15Al4Si16O54 · 17H2O |
| 9.DG.12 | Kenotobermorite | Ca4Si6O15(OH)2 · 5H2O |
| 9.DG.15 | Foshagite | Ca4(Si3O9)(OH)2 |
| 9.DG.20 | Jennite | Ca9(Si3O9)2(OH)8 · 8H2O |
| 9.DG.20 | Kamenevite | K2TiSi3O9 · H2O |
| 9.DG.25 | Paraumbite | K3Zr2H(Si3O9)2 · nH2O |
| 9.DG.25 | Umbite | K2(Zr,Ti)Si3O9 · H2O |
| 9.DG.30 | Sørensenite | Na4SnBe2Si6O16(OH)4 |
| 9.DG.32 | Escheite | Ca2NaMnTi5[Si12O34]O2(OH)3 · 12H2O |
| 9.DG.35 | Xonotlite | Ca6(Si6O17)(OH)2 |
| 9.DG.40 | Hillebrandite | Ca2(SiO3)(OH)2 |
| 9.DG.45 | Zorite | Na8(Ti,Nb)5(Si6O17)2(OH,O)5 · 14H2O |
| 9.DG.45 | Chivruaiite | Ca4(Ti,Nb)5(Si6O17)2(OH,O)5 · 13-14H2O |
| 9.DG.50 | Haineaultite | (Na,Ca)5Ca(Ti,Nb)5(Si6O17)2(OH,F)8 · 5H2O |
| 9.DG.55 | Epididymite | Na2Be2Si6O15 · H2O |
| 9.DG.60 | Eudidymite | Na2Be2Si6O15 · H2O |
| 9.DG.65 | Elpidite | Na2ZrSi6O15 · 3H2O |
| 9.DG.65 | Patynite | NaKCa4[Si9O23] |
| 9.DG.67 | Whelanite | Cu2+2Ca6[Si6O17(OH)](CO3)(OH)3 · 2H2O |
| 9.DG.70 | Enricofrancoite | KNaCaSi4O10 |
| 9.DG.70 | Yusupovite | Na2Zr(Si6O15) · 2.5H2O |
| 9.DG.70 | Litidionite | KNaCuSi4O10 |
| 9.DG.70 | Fenaksite | (K,Na)4(Fe,Mn)2(Si4O10)2(OH,F) |
| 9.DG.70 | Manaksite | KNaMnSi4O10 |
| 9.DG.75 | Senkevichite | CsKNaCa2TiO[Si7O18](OH) |
| 9.DG.75 | Tinaksite | K2Na(Ca,Mn2+)2TiO[Si7O18(OH)] |
| 9.DG.75 | Tokkoite | K2Ca4[Si7O18(OH)](OH,F) |
| 9.DG.80 | Fluorcanasite | K3Na3Ca5Si12O30F4 · H2O |
| 9.DG.80 | Canasite | K3Na3Ca5Si12O30(OH)4 |
| 9.DG.85 | Miserite | K1.5-x(Ca,Y,REE)5(Si6O15)(Si2O7)(OH,F)2 · yH2O |
| 9.DG.90 | Frankamenite | K3Na3Ca5(Si12O30)(F,OH)4 · H2O |
| 9.DG.92 | Charoite | (K,Sr)15-16(Ca,Na)32[Si6O11(O,OH)6]2[Si12O18(O,OH)12]2[Si17O25(O,OH)18]2(OH,F)4 · ~3H2O |
| 9.DG.95 | Yuksporite | K4(Ca,Na)14(Sr,Ba)2(◻,Mn,Fe)(Ti,Nb)4(O,OH)4(Si6O17)2(Si2O7)3(H2O,OH)3 |
| 9.DG.97 | Eveslogite | (Na,K,Ca,Sr,Ba)48 [(Ti,Nb,Mn,Fe2+)12Si48O144(OH)12](F,OH,Cl)14 |
Fluorescence of Wollastonite-1A
The mineral is slightly luminescent under long-wave (366 nm) ultraviolet radiation, the luminescence tint being light blue. The powders show a strong cathodoluminescence in blue tints, which is also evident on some thin sections and associates with the bright green cathodoluminescence color reported previously
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 Wollastonite-1A
mindat.org URL:
https://www.mindat.org/min-7369.html
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Please feel free to link to this page.
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References for Wollastonite-1A
Reference List:
Localities for Wollastonite-1A
Showing 10 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.
Italy | |
| King (n.d.) +1 other reference |
Japan | |
| Henmi et al. (1983) |
| Handbook of Mineralogy. |
Mexico | |
| Brenker et al. (2002) |
Romania | |
| Marincea et al. (2026) |
| Klaproth (1802) |
Russia | |
| Zhitova et al. (2025) |
USA | |
| PXRD by John Attard (Attard XRD Services, San Diego) |
| University of Arizona Mineral Museum ... |
| [micromounts@yahoogroups.com] |
In-Ko-Pah Gorge, Boulder Park, Imperial County, California, USA