Glaze material · Colorants
Manganese dioxide
Also sold as: manganese oxide, manganese carbonate
Browns, toward purple with alkaline fluxes; metallic surfaces in high amounts with copper.
In published recipes
Used in 534 of 10,859 glaze recipes (4.9%)
Typical amount when present
3% of the dry batch — half of recipes fall between 2% and 6.1%.
Fired surface of those recipes
Glossy 58% · Satin 14% · Matte 14% · Satin matte 14%
Most often mixed with
Materials that appear in the same recipes most often.
Chemistry
- Raw formula
- MnO2
- Molecular weight
- 87
- Fired formula
- MnO
- Equivalent weight
- 87
- manganese carbonate MnCO3: 115 → MnO, eq. wt. 115
From Linda Arbuckle's materials table. Mineral formulas are idealized; buy an analysis for the bag you have. Equivalent weight is the weight that supplies one molecule of the fired oxide — the number glaze calculation uses.
What potters should know
The carbonate is weaker but disperses better than the dioxide. Fritted with alumina it becomes the pink stains.
Handling and safety
Contains manganese compounds. Chronic inhalation causes manganism (neurotoxicity); use respiratory protection during dry mixing.
Dry ceramic materials generate respirable silica dust. Use a NIOSH-approved N95 or P100 respirator and adequate ventilation when mixing dry, and wet-clean surfaces.
This information is provided for planning purposes and is derived from publicly available sources including OSHA regulations, NIOSH guidance, and manufacturer safety data sheets. It does not constitute professional safety advice. Consult your material suppliers' SDS documents and applicable local regulations for authoritative safety guidance.
Questions
- How much Manganese dioxide do potters use in a glaze?
- Across 534 published glaze recipes containing it, the typical amount is 3% of the dry batch, with half of recipes between 2% and 6.1%. Colorants and additives sit far lower than fluxes and glass formers; treat these as a range to test around, not a target.
- What cone is Manganese dioxide used at?
- It appears in recipes across the range; the most common cones among published recipes are cone 6, cone 10, cone 9. Where a material sits depends on the rest of the recipe more than on the material itself.
- Is Manganese dioxide safe to use?
- It carries a specific hazard flag: Contains manganese compounds. Chronic inhalation causes manganism (neurotoxicity); use respiratory protection during dry mixing. Read the supplier's SDS and follow local rules before using it, and never assume a glaze is food-safe without testing.
Related materials
| Glaze material | recipes | typical |
|---|---|---|
| Red iron oxide | 2,413 | 4% |
Sources. Usage figures are computed by Claybench over 10,859 glaze recipes compiled from publicly shared community recipe collections (snapshot 2026-02-27) — counts only; no recipe is reproduced, and the figures describe that collection, not every recipe in existence. Material roles and notes are paraphrased from Linda Arbuckle's Ceramic Materials handout unless noted. Hazard notes summarise supplier SDS guidance; read the SDS for the product you buy.
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