Ceramic Glaze Colorant Chart

A ceramic glaze color chart tells you which color family a colorant gives: cobalt gives blue, copper gives green in oxidation and red in reduction, chrome gives green, and iron gives browns. Pick your colorant, amount, cone and atmosphere below to see sourced notes. These are color families, not exact swatches.

How to use the glaze colorant chart

• Choose the colorant. The options are cobalt carbonate or oxide, copper carbonate or oxide, red or black iron oxide, chrome oxide, manganese dioxide, rutile, nickel oxide, or a commercial stain.
• Pick the percentage range of that material you plan to add to the dry base recipe.
• Select your firing range: low fire (cone 06–04), mid-range (cone 5–6) or high fire (cone 9–10).
• Choose oxidation or reduction.
• Optionally, pick the dominant base glaze trait, such as high zinc, barium, magnesium, calcium, boron or alkali, or an opacified base.
• Read the color family summary, the conditional findings, the atmosphere notes and the safety notes. Then read the source quotes. The tool lists every stored statement for your colorant and highlights the ones related to your choices.

A highlighted quote may still depend on conditions your glaze does not meet, such as lead, low alumina or a second colorant. Whatever the result says, fire a test tile in your own base glaze and kiln before you mix a full batch.

How the chart works: colorant, amount, atmosphere, base

The tool does not use a formula to predict color. It is a lookup with four parts.

• Color family. The headline is a general color family summarized from Digitalfire and Mason statements.
• Conditional findings. Some sources publish an effect only at a narrower amount, such as purple at 1–2% cobalt in high-magnesia glazes, yellowish chrome tints below 0.5%, or metallic manganese at about 20%. The tool never applies these to a whole percentage range. It shows each one with its exact published limit and, where the basis matches, says whether that limit falls outside, within part of, or across your selected range.
• Matching percentage bases. A limit is only compared with your amount when both refer to the same material. A cobalt limit stated as CoO is compared with cobalt carbonate after converting at 63% effective CoO, and the cobalt-carbonate recipe is not compared with a cobalt oxide amount. Quotes that do not say which form they mean are shown without a range match: the 1–2% cobalt purple, the 7% copper metallic green (carbonate or oxide not stated) and the 0.5% and 3–4% iron reduction notes (red or black iron oxide not stated).
• Conflicting statements. If a statement names a specific atmosphere or temperature that conflicts with your choice, it is not highlighted. For example, an oxidation-only copper statement or the reduction-only iron yellow recipe is marked “No” when you pick the other atmosphere.
• Safety and reminder. Each result ends with the colorant’s safety notes and a reminder to fire a test tile.

Two conversions matter when you swap one form of a colorant for another. Digitalfire notes that cobalt carbonate has 63% effective stain content, while cobaltic oxide is 90% CoO. In practice, you need noticeably more carbonate than oxide to get the same strength of blue. For example, 1–3% cobalt carbonate works out to roughly 0.63–1.89% CoO.

Why base glaze chemistry changes glaze color

The same colorant can fire to very different colors depending on the fluxes around it. Here are some examples from Digitalfire:

• In high-magnesia glazes, 1–2% cobalt alone will give purple. The source does not say whether that means carbonate or oxide. A separate statement gives purples with high MgO at 1% or more CoO.
• Barium glazes are known for matte turquoise colors with copper.
• Alkalies or high boron shift copper green toward blue.
• Iron fires yellowish with calcia. A yellow opaque from 3–4% iron is published only for one specific barium and zircon base in reduction.
• Chrome moves toward grass green with calcia but turns brown with zinc, because it forms zinc chromite.
• Nickel is especially variable: steel blue with zinc, tan with calcium, brown with barium and grey in lead glazes.

Commercial stains follow the same logic. The Mason Stains reference guide states that “Zinc Oxide influences the color in a glaze more than any other element.” It also says some stains need a glaze containing 6.7 to 8.4% CaO (12–15% CaCO3). The guide adds that firing temperatures can only be a rough guide, because the cycle, atmosphere and rate of cooling all affect the color. Check each stain’s listed sensitivities before you choose a base.

Safety belongs on any colorant chart. Digitalfire warns that significant manganese and copper metal fumes are generated at cone 10. It also says high-manganese metallic glazes must not be used on food surfaces, and that copper is volatile enough to affect other pieces in the same firing.

Methodology & sources

The tool contains two kinds of text.

• Verbatim source excerpts. Text in quotation marks and the source-statement table are exact excerpts from the pages below, which were checked in November 2026. Original spelling is kept, and any punctuation we add sits outside the quotation marks. Where one source passage mixes a general note with a condition-specific recipe, the tool shows them as separate excerpts from the same page.
• Editorial summaries. The color family headline, the cobalt conversion notes, the conditional-finding labels, the related/conflict markers and this page’s prose are our summaries of those excerpts and are not shown in quotation marks.
• Percentage basis. A published percentage is compared with your selected range only when the source names the same material form you picked (or, for CoO limits, after converting cobalt carbonate at 63%). When the source does not state the form, as with the 7% copper, 0.5% iron, 3–4% iron and 1–2% cobalt notes, the result reads “basis not stated; shown without a range match”.

Two Digitalfire excerpts call ZnCr2O4 “zinc chromate”. That compound is zinc chromite, so the tool adds an editor’s note to both. Where no source gives a percentage or color for your selection, the tool says so instead of guessing. Hamer’s and Rhodes’ texts and per-percentage swatches were left out because we did not verify them.

• Digitalfire: Cobalt oxide (CoO)
• Digitalfire: Copper oxide (CuO)
• Digitalfire: Iron oxide (Fe2O3)
• Digitalfire: Chrome oxide (Cr2O3)
• Digitalfire: Manganese dioxide (MnO2) and MnO
• Digitalfire: Nickel oxide (NiO)
• Digitalfire: Rutile and TiO2
• Hazard pages: manganese dioxide, chrome oxide, cobalt carbonate, copper carbonate, zinc, barium
• Mason Color Works: Mason Stains reference guide

Last updated: November 2026

FAQ

What color does copper give in a glaze?

According to Digitalfire, copper oxide produces clear green colors in most glazes under normal oxidizing conditions. In reduction it can give blood-red and fire-red colors, and in barium glazes it is known for matte turquoise.

How much cobalt do I need for blue?

Digitalfire notes that cobalt is powerful and often less than 1% will give strong color. Cobalt carbonate has about 63% effective stain content, so you need more carbonate than oxide for the same strength.

Why did my chrome green glaze turn brown?

Chrome in zinc glazes tends to form the stable crystalline compound zinc chromite (ZnCr2O4), which is brown. Use a zinc-free base if you want chrome greens or chrome-tin pinks.

Does this chart show exact glaze colors?

No. It shows color families based on published references, because the real result depends on your base glaze, clay body, application thickness and firing. Always fire a test tile before mixing a full batch.

Are manganese and copper glazes safe to fire?

Digitalfire warns that significant manganese and copper metal fumes are generated at cone 10, so ventilate the kiln well. It also says high-manganese metallic glazes must not be used on food surfaces.

Related guides

• How to Mix Dry Glaze Powder for Ceramics