Cornwall Stone Substitute (Laguna SG919)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Feldspars and stones
- Formula
- SiO₂ 73%, Al₂O₃ 16%, K₂O 7.4%, Na₂O 2.6%, CaO 0.6%, TiO₂ 0.2%
- Also called
- Cornwall Stone Substitute, Cornwall Stone - Laguna Sub Blend, SG919, SG-919, GSG919, Laguna Cornwall Sub, Cornwall Stone sub by Laguna
- Made by
- Laguna Clay Co. (blend)
- Sold in
- US
- Replaces
- Cornwall Stone
- Source
- Clay-King product page 'Cornwall Stone Substitute' (SG919 Laguna Cornwall Sub analysis); same figures on Digitalfire (2026-08)
Laguna's blended Cornwall stone substitute (feldspar, quartz and a little kaolin), developed when natural Cornish stone became unavailable. It is nearly iron-free.
Oxide analysis and unity formula
Glazecalc has the analysis of Cornwall Stone Substitute (Laguna SG919) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Cornwall Stone Substitute (Laguna SG919) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 73 | 9.260 |
| Al₂O₃ | 16 | 1.196 |
| K₂O | 7.4 | 0.599 |
| Na₂O | 2.6 | 0.320 |
| CaO | 0.6 | 0.082 |
| TiO₂ | 0.2 | 0.019 |
- Equivalent weight
- 762.14
- Fired weight
- 762.14
- Loss on ignition
- 0%
The equivalent weight is the grams of Cornwall Stone Substitute (Laguna SG919) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Contains crystalline silica (10-25% quartz per Laguna's 2024 SDS); avoid breathing the dust.
Use it in a recipe
Add Cornwall Stone Substitute (Laguna SG919) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.