Cornwall Stone
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Feldspars and stones
- Status
- Discontinued 2006
- Formula
- CaO: 0.304; Na₂O: 0.340; K₂O: 0.356; Al₂O₃: 1.075; SiO₂: 8.10
- Also called
- Cornish Stone, Cornish Stone (natural), China stone, DF Cornish stone, Hard purple, Mild white
- Made by
- Goonvean (last producer); English China Clays until 1973
- Sold in
- UK
- Similar materials
- Cornish Stone (synthetic substitute) , H&G Cornwall Stone , Cornwall Stone Substitute (Laguna SG919) , Cornish Stone, Synthetic (Walker BA280)
- Source
- Glazecalc’s original data (2017), from a ceramics reference book
Typical formula. Not quarried since 2006; what is sold now are synthetic substitutes with different chemistry, so use the supplier’s analysis for those.
Oxide analysis and unity formula
Glazecalc has the analysis of Cornwall Stone as moles of each fired oxide per formula. The unity contribution is the moles of each oxide in the amount of Cornwall Stone that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Moles | Unity contribution |
|---|---|---|
| CaO | 0.304 | 0.304 |
| Na₂O | 0.340 | 0.340 |
| K₂O | 0.356 | 0.356 |
| Al₂O₃ | 1.075 | 1.075 |
| SiO₂ | 8.10 | 8.100 |
- Equivalent weight
- 667.93
- Fired weight
- 667.93
- Loss on ignition
- 0%
The equivalent weight is the grams of Cornwall Stone that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Fine dust contains respirable crystalline silica; avoid breathing it.
Use it in a recipe
Add Cornwall Stone to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.