Wollastonite (Vansil W)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Fluxes
- Formula
- CaO•SiO₂ (ideal CaSiO₃: CaO 48.28, SiO₂ 51.72)
- Also called
- Wollastonite, Vansil W-20, Vansil W-30, Vansil W-10, Wollastonite W-20, Wollastonite 325M, Calcium silicate (wollastonite)
- Made by
- Vanderbilt Minerals, LLC
- Sold in
- US
- Source
- Vanderbilt Minerals technical data 'VANSIL W Wollastonite, Low Aspect Ratio Grades' (W-20/W-30/W-40/W-50), rev 08/09/2018 (2018-08)
Natural calcium silicate, the wollastonite most US pottery suppliers sell (Laguna, Seattle Pottery Supply and Bailey stock Vansil grades). It supplies CaO and SiO2 together with no carbonate gas, so it causes less pinholing than whiting.
Oxide analysis and unity formula
Glazecalc has the analysis of Wollastonite (Vansil W) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Wollastonite (Vansil W) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| CaO | 44.9 | 0.953 |
| SiO₂ | 51.3 | 1.016 |
| Al₂O₃ | 0.9 | 0.011 |
| MgO | 1.6 | 0.047 |
- Equivalent weight
- 118.99
- Fired weight
- 117.68
- Loss on ignition
- 1.1%
The equivalent weight is the grams of Wollastonite (Vansil W) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Needle-shaped (acicular) mineral dust; avoid breathing it.
Use it in a recipe
Add Wollastonite (Vansil W) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.