Black Copper Oxide, also known as Cupric Oxide (CuO), has been used by potters as a coloring oxide for a very long time. It can work as a very strong flux and give glazes a speckled color appearance. This material reacts greatly to atmospheric changes. In reduction, the material can completely change color.  Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Red Copper Oxide is a colorant used in clay bodies and glaze recipes. It is the reduced form of Black Copper Oxide. Red Copper Oxide is maybe best known for its use in reduction atmosphere, producing beautiful reds in glazes. It can also be used in oxidation firings, where it will turn back into black copper oxide and produce very nice greens. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Ultrox is the brand name for zircon, an opacifier used in glaze recipes. Ultrox assures uniformity of opacity, texture and color in glazes. This material reduces the thermal expansion of glazes as well as reducing crazing.  Information gathered from Digitalfire Ceramic Materials Database.

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Tin Oxide is a white powder made by oxidizing high grade tin metal. In ceramics, tin oxide is typically used as an opacifier in glaze recipes to create strong white colors. It can also be used as a variegator in combination with other materials. When added to a glaze, tin oxide will cause the materials to clump together so make sure to sieve the glaze slurry. Information gathered from Digitalfire Ceramic Materials Database.

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Titanium Dioxide is a very fine grained powder known for its strong white pigment. It's white color is due to the fact that it crystallizes during cooling. It is not as effective of a whitener as other opacifiers. It can also be used as a variegator and or crystalizer in glaze recipes, creating interesting visual effects. Information gathered from Digitalfire Ceramic Materials Database.

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Burnt Umber is the calcined, or burnt, version of umber. In as little as 600°F, umber, a yellowish light brown, can turn into Burnt Umber, a rich red brown, and gets rid of the plasticity of umber. Burnt umber is commonly used as a stain in many clay bodies, slips, engobes, and glazes. Information gathered from Digitalfire Ceramic Materials Database.

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Ilmenite is mined from ore of titanium and iron. Its primary uses are to yield brown specks in clay bodies and glazes, similar to rutile, and can be used in small amounts in crystalline glazes. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Black Iron Oxide, also known as Ferrous Oxide (FeO), is red iron oxide that has been fired in a reduction atmosphere. Iron oxides are the most common colorants used in the ceramics industry. Black Iron Oxide specifically can be used as an alkaline flux in clay bodies and glaze recipes. In glaze: 1% of black iron oxide will give you a pale green  3% of black iron oxide will give a greenish gray color 8% will give you a black Information gathered from The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Red Iron Oxide is possibly the most common colorant in the ceramics industry. It is used in oxidation to create lovely browns, tans, and yellows. In reduction, red iron oxide becomes a flux, making the glazes melt off the ware.  Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Zinc Oxide is a material used in glaze recipes. It has been calcined to remove any of the excess water. It can be used in crystalline glaze or used as a flux in small amounts. The use of Zin Oxide also lowers thermal expansion. Information gathered from Digitalfire Ceramic Materials Database.

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Spanish Red Iron Oxide is a material that is similar to red iron oxide, but differs in some key ways. Spanish Red Iron Oxide has less iron and is less refined than the regular red iron oxide. Spanish Red Iron Oxide should only be used in a recipe when it is specifically called for it. 

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Yellow Iron Oxide is a coloring oxide used in many clay bodies and glaze recipes. Because yellow iron oxide fires red in oxidation, in can be used to achieve a red color in clay bodies without reducing the plasticity of the body, unlike red iron oxide. 

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Manganese Dioxide is a coloring oxide used in glaze recipes and clay bodies. In glazes, the addition of the colorant produces violets, browns, and metallics. In clay bodies, many people use the material to darken their clay or make black clay. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Granular Manganese is manganese dioxide that has not been ground into a fine powder. Granular Manganese is used to create speckles in clay and glazes, which ilmenite and rutile can do but are not as effective as granular manganese. To achieve speckles in a cone 4-6 clay body using 60-80 mesh, 0.2-0.3% is used. However, the granular particles will begin to bloat and bleed into glazes at a cone 6.  Information gathered from Digitalfire Ceramic Materials Database.

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Chromium Oxide is a refractory colorant that is used to add a green color to slips, clay bodies, and glazes. This material easily produces a green color at all furnace conditions, making it a fast colorant. In glazes, up to 1% will give you muted greens and up to 3% will give you opaque and greyish greens. In slips and clay bodies, up to 5% will give you a variety of grey-greens. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Cobalt Carbonate is a pinkish tan powder used to color slips and glazes. When used up to 1.5%, the powder will create shades of blue. Higher amounts of the powder will create a black. While cobalt carbonate disperses better into a slurry than cobalt oxide, the carbonate will produce carbon dioxide gas in the firing, meaning it can cause blistering and pinholes in the glaze it was added to. Cobalt Carbonate is often used instead of cobalt oxide because it is able to disperse itself in glazes better, yielding a more solid color rather than a patchy or speckled color that often shows itself when cobalt oxide is used. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Nickel Carbonate Green is a colorant commonly used in glaze recipes. It is the carbonate version of Nickel Oxide Green and allows for the color to be more evenly distributed in the glazed area of the ware. 

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Cobalt oxide is a very powerful colorant to get blues. Using less than 1% of the material will yield a very strong blue color in glazes. However, in most firings, there is not enough time for the material to properly disperse itself in the glaze, making it splotchy and speckled. To fix this issue, cobalt carbonate can be used instead.  Information gathered from The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Yellow Ochre is a natural clay material containing Yellow Iron Oxide. It is used as a colorant in clay bodies and glaze recipes producing tans, yellows, and red-browns. Information gathered from Digitalfire Ceramic Materials Database.

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Copper Carbonate is a colorant that can be used to make greens and blues in oxidation and reds and oxbloods in reduction. This material is also used heavily in raku glazes! Copper carbonate will mix better into slurries than its oxide counterpart. A little goes a long way, 0.5-3% being enough to create color in glazes. 

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Red Iron Oxide is possibly the most common colorant in the ceramics industry. It is used in oxidation to create lovely browns, tans, and yellows. In reduction, red iron oxide becomes a flux, making the glazes melt off the ware.  Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer. PLEASE NOTE:If you are mixing up a Steven Hill glaze that calls for "High Purity Red Iron Oxide," he gets his materials through another source - US Pigment. Steven has said that his Red Orange glaze will NOT turn out as expected if you use a different iron. Steven went on to tell me that using the US Pigment version of the high purity red iron oxide is not as critical in the Juicy Fruit glaze recipe.

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Rutile is the mineral name for the naturally occurring crystals of titanium dioxide. While this material does produce creams, yellows, and oranges, it is not considered a colorant but a variegator in glazes. It can produce crystalline, speckling, streaking, and mottling effects in glazes during cooling.  Rutile can be purchased as lite rutile, which is a calcined powder, dark rutile, a raw powder, and granular. It is best to use Lite rutile in glazes for less imperfections during firing. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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Silicon Carbide is a refractory, artificial compound primarily used to make kiln furniture to due its hardness and ability to withstand high heat and thermal shock. The material can also be used in glaze and slip recipes to do local reduction in an oxidation firing and to make crater and foam glazes, due to the gas it releases in firing. Information gathered from Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.

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