Glaze type · Iron glazes
Amber (iron)
Across 148 published recipes: mostly cone 10 and cone 6, fired in oxidation and reduction; Glossy, opaque.
Atmosphere
oxidation 46% · reduction 45% · neutral 5% · salt & soda 4%
Surface
Glossy 57% · Semi-glossy 16% · Matte 14% · Satin 7% · Semi-matte 6%
Transparency
opaque 35% · translucent 26% · transparent 24% · semi-opaque 15%
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 | 70% | 15.05% | 8.83–26.59% |
| Red iron oxide | 65% | 3.19% | 2–6.23% |
| Whiting | 60% | 14% | 7.3–19.84% |
| Custer feldspar | 43% | 29.5% | 21.98–41% |
| EPK | 43% | 8.8% | 4–13.02% |
| Dolomite | 40% | 12% | 6–19% |
| Bentonite | 39% | 2% | 1.98–2% |
| Nepheline syenite | 26% | 23.49% | 16.75–45% |
| Gerstley borate | 24% | 9.63% | 3.23–18% |
| Kaolin | 22% | 15% | 8.35–22.43% |
| Ball clay | 20% | 8.5% | 4.82–10.73% |
| Wollastonite | 18% | 14% | 10–18% |
| Zircopax | 16% | 14.7% | 10–17.42% |
| Barium carbonate | 16% | 20% | 5.5–30.8% |
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 | 48.81% | 43.51–54.66% |
| Al2O3 | 10.94% | 9.18–13.06% |
| B2O3 | 2.78% | 1.06–5.61% |
| Na2O | 1.95% | 1.17–3.29% |
| K2O | 2.82% | 1.82–3.78% |
| CaO | 9.53% | 6.29–12.57% |
| MgO | 1.23% | 0.24–2.65% |
| Fe2O3 | 3.27% | 1.87–5.04% |
What potters should know
Iron in glazes with barium, strontium or lead reads amber; in the aggregate, look at the iron level and the alkaline-earth fluxes above.
Related types
Questions
- What is a Amber (iron) glaze?
- In 148 published recipes, Amber (iron) glazes are mostly fired to cone 10 and cone 6 in oxidation and reduction, with a Glossy, opaque result. The defining materials are Silica, Red iron oxide, Whiting, Custer feldspar, EPK.
- What cone is Amber (iron) fired to?
- The most common cones in published recipes are cone 10 and cone 6; 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 Amber (iron) glaze?
- Median fired analysis: SiO2 48.81%, Al2O3 10.94%, B2O3 2.78%, Na2O 1.95%, K2O 2.82%, CaO 9.53%. 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
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