Glaze type · Surfaces & effects
Magnesium matte
Across 129 published recipes: mostly cone 6 and cone 10, fired in oxidation and reduction; Satin matte, opaque.
Atmosphere
oxidation 65% · reduction 31% · neutral 3% · salt & soda 1%
Surface
Satin matte 39% · Matte 37% · Semi-matte 9% · Satin 9% · Smooth matte 6%
Transparency
opaque 69% · semi-opaque 20% · translucent 8% · transparent 3%
Materials that define it
Share of recipes containing each material, and the typical amount when present. Materials link to their reference pages.
| Material | In recipes | Typical | Half of recipes |
|---|---|---|---|
| Silica | 77% | 17% | 11–22.9% |
| Dolomite | 61% | 16.12% | 8.45–20% |
| Whiting | 57% | 10% | 4.9–14.64% |
| EPK | 53% | 12.75% | 9.51–18.08% |
| Talc | 43% | 14% | 10.28–16.08% |
| Nepheline syenite | 29% | 27.2% | 20–35.6% |
| Kaolin | 28% | 20% | 9.2–25% |
| Bentonite | 27% | 2% | 2–2% |
| Custer feldspar | 26% | 40% | 28.45–40% |
| Potash feldspar | 19% | 41% | 32.05–46.96% |
| Gerstley borate | 19% | 12.15% | 10–16.93% |
| Cobalt carbonate | 17% | 2% | 1–4% |
| Cobalt oxide | 16% | 1% | 0.75–2% |
| Magnesium carbonate | 15% | 10% | 5–14.29% |
Typical fired chemistry
Median oxide analysis (weight %) across the recipes that report one, with the interquartile range. Silica and alumina set the melt; the fluxes and colorants make the family.
| Oxide | Median | Half of recipes |
|---|---|---|
| SiO2 | 53.12% | 46.13–57.52% |
| Al2O3 | 11.6% | 10.02–15.87% |
| B2O3 | 3.01% | 1.37–4.24% |
| Na2O | 2.15% | 1.53–3.38% |
| K2O | 2.44% | 1.55–4.35% |
| CaO | 8.28% | 5.46–10.2% |
| MgO | 4.63% | 3.52–6.44% |
| CoO | 1.04% | 0.62–2.38% |
What potters should know
Magnesium from dolomite, talc or magnesium carbonate gives the soft, buttery mattes and pastel colours this family is known for.
Questions
- What is a Magnesium matte glaze?
- In 129 published recipes, Magnesium matte glazes are mostly fired to cone 6 and cone 10 in oxidation and reduction, with a Satin matte, opaque result. The defining materials are Silica, Dolomite, Whiting, EPK, Talc.
- What cone is Magnesium matte fired to?
- The most common cones in published recipes are cone 6 and cone 10; the full distribution is on this page. Atmosphere matters as much as cone for this family: oxidation and reduction.
- What is the typical chemistry of a Magnesium matte glaze?
- Median fired analysis: SiO2 53.12%, Al2O3 11.6%, B2O3 3.01%, Na2O 2.15%, K2O 2.44%, CaO 8.28%. Treat these as the centre of a range, not a target — the same family spans different fluxes and cones.
Sources. Every figure is a statistic computed by Claybench over 10,859 glaze recipes compiled from publicly shared community recipe collections (snapshot 2026-02-27); no recipe is reproduced. Colour-chemistry notes are paraphrased from Linda Arbuckle's Ceramic Materials handout.
Colorant and flux notes touch on materials with handling hazards (barium, cobalt, chrome, manganese, lead in historic recipes). Read each material's page and its supplier SDS before mixing; test any food surface.
Claybench checks a glaze against your clay body and cone before it lands on a plan
Recipes, materials, hazards and cone fit — the same reference behind this page, inside the studio planner.