Miscellaneous
Clays and Chemicals
Alumina Hydrate A
source of alumina in glazes, stays in suspension long and aids
AL2O3 • 3H2O
in glaze adhesion.
Alumina Oxide - Al2O3 A
neutral or intermediate oxide which stabilizes fluxes and acids. Responsible
for stiffness (fluidity) of a glaze.
A calcined form of alumina hydrate.
Barium Carbonate - BaCO3 A
source of barium oxide for glazes. An inactive flux producing mattness. Also
used to neutralize sulfates in clays to prevent scumming. Dust is toxic.
Bone Ash - Ca3(PO4)2 A
source of calcium and phosphate. Added to clay bodies to lower the maturing
temperature. It acts as an opacifer when used in glazes. Also gives texture in
low fire glazes.
Borax - A
low fire flux that produces smooth finishes. A source of sodium
Na2O
• 2B2O3 • 10H2O
and boric oxide. Soluble in water.
Chromium Oxide - Cr2O3 Used in ceramics mainly for green colors.
Reduction darkens the green color. Dust is toxic.
CMC Gum An
organic cellulose gum used to thicken and suspend glazes.
Cobalt Carbonate - CoCO3 A lavender powder used to introduce cobalt
into the ceramic compounds giving good shades of blue, and when manganese is
added can give purple. Dust is toxic.
Cobalt Oxide - CoO An
extremely strong blue stain. Used for brushing oxide decorations and as a glaze
colorant.
Copper Carbonate - CuCO3 The most
popular source for copper in ceramics. Source of light greens and occasionally
copper reds in reduction.
Copper Oxide, Black - CuO Historically proven to be the
oldest glaze colorant known. Copper oxide normally gives a green color but
reducing conditions cause it to give a red due to the formation of colloidal
copper. It is an active flux. Dust is toxic.
Dolomite - Mg Ca(CO3)2 High temperature flux. Used to introduce
calcium and magnesia. Gives a matt-surfaced buttery glaze finish.
Darvan 7 A
deflocculant with a wider deflocculation curve, thus it is easier to use and
does not deteriorate molds as fast as sodium silicate.
Kaolin EPK A
kaolin valued for its plasticity and whiteness. Used in clay bodies and glazes.
A source of alumina. Also known as
China Clay.
Kaolin
Helmer A
kaolin known for its remarkable flashing quality in wood, salt and pit firing.
Feldspar Custer A
potash spar from
Feldspar G-200 A
potassium feldspar. Low in impurities. Good for high fire stoneware and glaze
formulation.
Feldspar Kona F-4 A
widely used soda spar from the eastern
Gerstley Borate Used
as a low temperature flux. A substitute for colemanite. Mined in
IMCO Borate A
blended product designed to be a direct replacement for Gerstley Borate. Unlike other substitutes, IMCO Borate
has the same physical properties as Gerstley Borate. It mixes with water to form a creamy
slurry that gels and keeps the glaze from settling. It melts at cone 08 and becomes fluid at
cone 06.
IMCO
Ione Kaolin A
California kaolin. It fires white and has low shrinkage.
Iron Oxide/Black - FeO A
glaze colorant used to produce browns and greens. Ferrous oxide.
Iron Oxide/Red - Fe2O3 A
less concentrated form of black iron oxide. Ferric oxide.
Lithium Carbonate - Li2CO3 Source of
lithia. Reduces thermal expansion. Acts as a high temperature flux and
increases the firing range and brightens the glaze.
Magnesium Carbonate Major
source of magnesium in glazes. In low temperatures it is a
MgCO3
refractory, at higher temperatures it acts as a flux. It also gives strength, opaqueness,
hardness and reduces shrinkage.
Manganese Dioxide - MnO2 Gives
blacks, purples and browns to glazes and clay bodies. Dust is toxic.
Manganese Carbonate A
weak coloring agent. A powerful
flux.
MnCO3
Nepheline Syenite A
feldspathoid good for introducing sodium. A substitute for normal
K2O • 3Na2O • 4AL2O •
9SiO2 feldspars
in clay and glazes used to lower the melting point.
Nickel Carbonate - NiCO3 Essentially
a weaker form of the oxide. Gives blues, browns and grays. Used as a modifier
of other stronger oxides such as cobalt and chrome. Dust is toxic.
Nickel Oxide - NiO Black
nickel produces browns, blues, grays and yellow in glazes. Can also tone down intense colorants
such as cobalt and coppe .
Petalite - A
lithium feldspar used as a source of lithium and silica in medium
Li2O • AL2O • 8SiO3 and
high temperature clay bodies.
PV Clay Used
as a flux in clays and glazes.
Pumice Volcanic
Ash, a type of feldspar used in glazes.
Purelube A
substitute for plastilube.
Rutile Natural
titanium dioxide with a small amount of iron. Gives a tan yellow color.
Mottling effects can occur especially in lead and low sodium glazes.
Silica - SiO2 (
Soda Ash - Na2CO3 Sodium
Carbonate. It is often used as a deflocculant in clay slips and as an active
flux in glazes.
Sodium Silicate - A
major deflocculant in casting slip.
Pure Sodium Silicate must be
Na2
• SiO2 mixed
with water in a 50/50 solution.
Spodumene A
lithium feldspathoid used in stoneware and porcelain bodies and
LiO2 • Al2O3 •
4SiO2 glazes
to replace feldspar. In clay bodies it reduces thermal expansion.
Strontium Carbonate Used
in glazes to improve the hardness and lower the solubility.
SrCO3 When
combined with other fluxes it improves the glaze and extends the firing range.
Talc - Protech A
California talc for use in glazes. In low fire clay bodies, it gives better
work ability and slightly yellower color than
Titanium Dioxide - TiO2 A major opacifier. Insoluble in water.
Tin Oxide - SnO2 Used
to produce smooth, opaque and semi-opaque white glazes. Aids in the development
of copper reds.
Whiting Calcium
carbonate. Source of calcia. High temperature flux used to add hardness to a
glaze.
Wax Resist A
wax and water emulsion applied to ceramic pieces to prevent the adhesion of raw
glaze.
Wollastonite - CaSiO3 Calcium
silicate. Source of calcia and
silica. Used to reduce shrinkage in clay bodies and glazes during firing.
Zinc Oxide - ZnO A
high-fire flux that reduces thermal expansion. Increases strength of glazes and
helps produce smooth surfaces.