Flint (UK calcined)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Silica
- Formula
- SiO₂ 96.35%, TiO₂ 0.02%, Al₂O₃ 0.35%, Fe₂O₃ 0.07%, MgO 0.05%, CaO 1.29%, K₂O 0.1%, Na₂O 0.09%, LOI 1.26%
- Also called
- Calcined flint, Water ground flint, Flint (damp/dry), Valentine FL003, Potterycrafts P3319, CTM 51 Flint, Water Ground, Bath Potters Flint
- Sold in
- UK
- Source
- Valentine Clays technical data sheet 'Flint (Damp/Dry)' (mean values) (2024-07)
UK 'flint' is calcined flint pebble, not ground quartz: about 96% SiO2 with 1.3% CaO and 1.3% LOI. Valentine says it raises thermal expansion when added to a glaze. US recipes that say 'flint' mean ground quartz.
Oxide analysis and unity formula
Glazecalc has the analysis of Flint (UK calcined) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Flint (UK calcined) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 96.35 | 59.929 |
| TiO₂ | 0.02 | 0.009 |
| Al₂O₃ | 0.35 | 0.128 |
| Fe₂O₃ | 0.07 | 0.016 |
| MgO | 0.05 | 0.046 |
| CaO | 1.29 | 0.860 |
| K₂O | 0.1 | 0.040 |
| Na₂O | 0.09 | 0.054 |
- Equivalent weight
- 3737.15
- Fired weight
- 3690.06
- Loss on ignition
- 1.26%
The equivalent weight is the grams of Flint (UK calcined) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Respirable crystalline silica, including some cristobalite; use a suitable respirator.
Use it in a recipe
Add Flint (UK calcined) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.