Pegmatita (Prodesco)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Feldspars and stones
- Formula
- SiO₂ 75%, Al₂O₃ 14%, Na₂O 7%, K₂O 1.7%, CaO 1.1%, LOI 1.2%
- Also called
- Pegmatita, Prodesco 50117800, Pegmatite (Spain)
- Made by
- Sold under the Prodesco S.L. brand (Manises, Valencia, Spain); the mine is not stated
- Sold in
- EU
- Similar materials
- FFP 45 Feldspar , Cornish Stone (synthetic substitute)
- Source
- Prodesco technical sheet 'Pegmatita', code 50117800, v1.4 (04/06/2026) (2026-06)
A sodic pegmatite: soda feldspar with a lot of quartz, sold to Spanish potters. It is a stiffer, more siliceous flux than soda feldspar, used somewhat like Cornish stone.
Oxide analysis and unity formula
Glazecalc has the analysis of Pegmatita (Prodesco) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Pegmatita (Prodesco) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 75 | 8.288 |
| Al₂O₃ | 14 | 0.912 |
| Na₂O | 7 | 0.750 |
| K₂O | 1.7 | 0.120 |
| CaO | 1.1 | 0.130 |
- Equivalent weight
- 663.99
- Fired weight
- 656.02
- Loss on ignition
- 1.2%
The equivalent weight is the grams of Pegmatita (Prodesco) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: High in free quartz (about 75% SiO2 overall); the dust contains respirable crystalline silica. Avoid breathing it.
Use it in a recipe
Add Pegmatita (Prodesco) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.