Glaze type · Copper & chrome
Turquoise (alkaline copper)
Across 181 published recipes: mostly cone 6 and cone 10, fired in oxidation and reduction; Glossy, opaque.
Atmosphere
oxidation 73% · reduction 19% · neutral 6% · salt & soda 2%
Surface
Glossy 58% · Matte 19% · Semi-glossy 10% · Satin 7% · Smooth matte 6%
Transparency
opaque 52% · semi-opaque 17% · translucent 17% · transparent 13%
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 |
|---|---|---|---|
| Copper carbonate | 80% | 3% | 2.5–4% |
| Silica | 77% | 19% | 8.33–27% |
| Bentonite | 50% | 2% | 2–2.28% |
| Whiting | 45% | 11% | 9–13.62% |
| Nepheline syenite | 30% | 52.74% | 30–60% |
| EPK | 28% | 9% | 6–16.47% |
| Ball clay | 27% | 8.66% | 6.2–10.5% |
| Lithium carbonate | 24% | 3% | 2–3.9% |
| Dolomite | 23% | 4% | 3.7–10.45% |
| Strontium carbonate | 23% | 20.9% | 12.25–25% |
| Gerstley borate | 21% | 14.01% | 9.88–21.85% |
| Barium carbonate | 19% | 27.47% | 23.4–38.2% |
| Zinc oxide | 19% | 5.3% | 3–8% |
| Ferro frit 3134 | 19% | 23.4% | 18.6–36.7% |
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 | 51.52% | 43.7–55.74% |
| Al2O3 | 10.17% | 7.96–13.03% |
| B2O3 | 4.78% | 3.17–6.67% |
| Na2O | 3.74% | 1.9–5.3% |
| K2O | 2.65% | 1.66–3.96% |
| CaO | 6.99% | 2.88–10.4% |
| CuO | 1.86% | 1.28–2.54% |
What potters should know
Copper with an alkaline flux gives turquoise — look for the sodium and lithium sources and the frits in the material list above.
Related types
Questions
- What is a Turquoise (alkaline copper) glaze?
- In 181 published recipes, Turquoise (alkaline copper) glazes are mostly fired to cone 6 and cone 10 in oxidation and reduction, with a Glossy, opaque result. The defining materials are Copper carbonate, Silica, Bentonite, Whiting, Nepheline syenite.
- What cone is Turquoise (alkaline copper) 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 Turquoise (alkaline copper) glaze?
- Median fired analysis: SiO2 51.52%, Al2O3 10.17%, B2O3 4.78%, Na2O 3.74%, K2O 2.65%, CaO 6.99%. 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.
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Recipes, materials, hazards and cone fit — the same reference behind this page, inside the studio planner.