How much G-200 feldspar do potters use in a glaze?

Across 320 published glaze recipes containing it, the typical amount is 34% of the dry batch, with half of recipes between 20% and 43.6%. 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 G-200 feldspar used at?

It appears in recipes across the range; the most common cones among published recipes are cone 10, cone 6, cone 9. Where a material sits depends on the rest of the recipe more than on the material itself.

Is G-200 feldspar safe to use?

It carries no specific hazard flag beyond the general rule for all dry ceramic materials: avoid breathing the dust and read the supplier's SDS.

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Glaze material · Fluxes, feldspars & frits

G-200 feldspar

Also sold as: G-200 HP

A potash feldspar, interchangeable with Custer in most recipes.

fluxglass formerstiffens the melt (alumina)Contributes: K₂O · Na₂O · Al₂O₃ · SiO₂

In published recipes

Used in 320 of 10,859 glaze recipes (2.9%)

Typical amount when present

34% of the dry batch — half of recipes fall between 20% and 43.6%.

Fired surface of those recipes

Glossy 74% · Satin 10% · Matte 9% · Satin matte 6%

Cones where it appears

Share of recipes containing this material that fire to each cone.

Most often mixed with

Materials that appear in the same recipes most often.

Silica83%EPK67%Whiting64%Dolomite35%Bentonite32%Red iron oxide30%Zinc oxide27%Tin oxide25%

Chemistry

Raw formula: K₂O·Al₂O₃·6SiO₂
Molecular weight: 556
Fired formula: K₂O·Al₂O₃·6SiO₂
Equivalent weight: 556
: idealized potash feldspar

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

Same job as any potash spar: flux with alumina and silica at high fire. The HP grade replaced the original when the deposit changed.

Handling and safety

Crystalline silica: the primary respiratory hazard in a ceramic studio (silicosis with chronic exposure). Wet processes, ventilation and a fitted respirator when dry.

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 G-200 feldspar do potters use in a glaze?: Across 320 published glaze recipes containing it, the typical amount is 34% of the dry batch, with half of recipes between 20% and 43.6%. 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 G-200 feldspar used at?: It appears in recipes across the range; the most common cones among published recipes are cone 10, cone 6, cone 9. Where a material sits depends on the rest of the recipe more than on the material itself.
Is G-200 feldspar safe to use?: It carries no specific hazard flag beyond the general rule for all dry ceramic materials: avoid breathing the dust and read the supplier's SDS.

Related materials

Glaze material	recipes	typical
Custer feldspar	2,210	37.5%
Potash feldspar	1,446	36%

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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