RAW MATERIALS GLOSSARY - greatclay.com

1 RAW MATERIALS GLOSSARY . Pyrophilite or Pyrax (200 mesh) Silica Sand (60 mesh) Tin Oxide SnO2. Similar to talc. Reduces thermal expansion in clay bodies. A much coarser grind of Silica used with or as an inexpen- The best and most expensive opacifier. Produces even, Can use up to 20% in formula. sive substitute of grog. Softens at cone 9. opaque glazes. Normal usage is from 2-10%. Twice the SiO2 .. SiO2 .. strength as Superpax and Zircopax. Al2O3 .. Silicon Carbide FFF (SiC) Titanium Dioxide (TiO2). Fe2O3 ..10. A very fine form of silicon carbonate. Used in glazes with An opacifier which promotes matte to semi-matte glazes. CaO ..02. copper carbonate and tin oxide to produce reds. Produces crystal effect at 6-15%. Impure forms of titaniu Na2O ..03. Toxic if inhaled. are rutile and ilmenite. Redart (200 mesh) Sodium Bicarbonate (NaHCo3) Ultrox A good, clean, red low-fire clay from the Cedar Heights Co.

2 A very stable, reliable opacifier widely used in large com- A water soluble flux agent. Combined with soda ash, it is a in Ohio. Not very plastic. The addition of bentonite is mercial potteries. Not as potent as Tin Oxide but stronger good, non-toxic substitute for rock salt in salt firing. suggested in a clay body. Makes a very good low-fire slip. than Superpax. SiO2 .. Sodium Carbonate (Na2Co3). Al2O3 .. Volcanic Ash (Pumice). Soda Ash. Used as a deflocculant in casting slips, helps Fe2O3 .. make Egyptian paste and small amounts in clay bodies gives Used as a flux in glazes and added to earthenware clay bo TiO2 .. increased strength and reduced shrinkage. ies for aiding in thermal shock resistance during pit and raku firings. CaO ..23. MgO .. Spanish Iron Oxide Whiting (CaCo3). K2O .. Fires dark brown to black.

3 A semi-refractory colorant applied as surface decoration under or over a glaze. Calcium Carbonate. The most common form of calcium i Na2O ..40 ceramics. Used as a flux in glazes and clay bodies and ad P2O5 ..17 Spodumene (200 mesh) durability and hardness to glazes.. A feldspar high in lithium that reduces thermal expansion in Wollastonite (CaSiO3). clay bodies and brightens blue glazes. Roseville Stoneware (200 mesh) SiO2 .. A natural source of calcium silicate used in glazes and cla Best if used in the cone 6-8 range but can be used in a cone bodies. Replaces silica and whiting. Al2O3 .. 10 body. Darker than Goldart and not as high in sulphur. Fe2O3 ..45 XX Sagger (200 mesh). SiO2 .. CaO .. A good, white ball clay from K-T Clays in Kentucky. Al2O3 .. MgO ..61 Lower in iron than OM4. Good plasticity.

4 Fe2O3 .. K2O ..51 SiO2 .. TiO2 .. Na2O ..22 Al2O3 .. MgO ..21 Li2O .. Fe2O3 ..07. CaO ..37. Na2O ..31 TiO2 .. Strontium Carbonate (SrCo3). K2O .. CaO ..50. Used in clay bodies for less pinholing and blistering in MgO ..30. S ..03 glazes. Improves hardness and lowers solubility in glazes. K2O ..90.. Extends glaze firing range. PCE ..Cone 23 Na2O ..30. Superpax ZrO4, SiO2 .. Rutile (TiO2, FeO) Powder PCE ..Cone 32. Zirconium silicate opacifier. Impure form of titanium dioxide. Contains iron, chromium Used in glazes as an opacifier and to control texture, color and vanadium oxides. Creates ivory, yellows, tans. Heavy Yellow Ochre (2 FeO3, 3H2O). stability and craze resistance. Smaller particle size then percentages in glaze breaks up colors and gives matte and Zircopax for better water dispersion. A weaker form of yellow iron oxide due to the high conte crystal surfaces.

5 Of clay. T-7 Kaolin (200 mesh). Salt Lick (200 mesh) A good, white kaolin used in basic glaze and slip formulas. Zinc Oxide (ZnO). A stoneware clay mined directly below Goldart. The sandy SiO2 .. A flux which causes more vibrant colors, a glossier glaze texture makes it less plastic, with less sulphur than Goldart . Al2O3 .. finish, increases maturing temperature and reduces crazing SiO2 .. 18-28% zinc glazes produce crystals when cooled slowly. Fe2O3 ..36. Al2O3 .. TiO2 .. Zircopax Plus ZrO2, SiO2. Fe2O3 .. P2O5 ..10 Zirconium silicate opacifier. 94-96%. TiO2 .. CaO ..22 Used much the same way as Superpax, but has larger part MgO ..01 cle size. A little stronger and more economical to use than MgO ..50 MnO ..01 regular Zircopax. CaO ..20 SO3 ..02. Na2O ..10 Na2O ..01. K2O .. PCE ..Cone 35 *PCE stands for Pyrometric Cone Equivalent.

6 Deter- .. mines how refractory a material is. Clay is fired with PCE .. Talc Nytal 100 HR (200 mesh) cones and when material softens, the number of the co A high resistant talc requiring less sodium silicate in slips. melting at that point is the PCE. Sapphire (200 mesh) or * stands for Loss on Ignition. Summarizes the Mainly used in low-fire slips, earthenware bodies and raku #6 Tile Clay (200 mesh) components within a raw material that burn away and bodies. Increases resistance to thermal shock. Produced in These two clays are virtually identical. Very plastic, clean upstate New York. are lost as gases. and white. Both mines are owned by Imerys. SiO2 .. SiO2 .. Al2O3 ..30. Al2O3 .. Fe2O3 ..20. Fe2O3 ..35. CaO .. TiO2 .. MgO .. CaO ..43 Na2O ..30. MgO ..58 .. Na2O ..04.. PCE ..Cone 35. 49. RAW MATERIALS GLOSSARY .

7 Goldart (200 mesh) Iron Oxide Black (Fe3O4) Molochite -30 (30 mesh) and A very plastic air-floated secondary clay from Cedar Heights. Ferrous Oxide. Not as popular as red iron oxide due to its Molochite -200 (200 mesh). Can be used as a ball clay or fireclay. Fairly high in sulfur minimal color range. A white grog made from ground up high-fired porcelain po content. tery or calcined kaolins. Used in porcelains and white clay SiO2 .. Iron Oxide Red (Fe2O3) bodies. Al2O3 .. Ferric Oxide. The most popular form of iron oxide. Colors SiO2 .. Fe2O3 .. range from yellow, tan, red, brown and black. Used in iron Al2O3 .. TiO2 .. saturate glazes such as tenmouku, aventurine and oilspot. Fe2O3 .. Toxic in large amounts if inhaled. CaO ..08 TiO2 ..08. MgO ..22 CaO ..10. Iron Oxide Yellow (Fe2O3). K2O .. MgO ..10.

8 A stronger version of yellow ochre but weaker than red iron Na2O .. K2O .. oxide due to its hydrated form and high clay content. So3 ..24 Na2O ..10.. Kentucky Stone (200 mesh). PCE ..Cone 29 A good plastic ball clay with natural sands from Kentucky. Mullite 35 (35 mesh) and Less sulphur than Goldart. Mullite 48 (48 mesh). Gold Label (200 mesh) SiO2 .. Calcined Kyanite. Used in clay bodies, kiln shelves, posts Produced by Old Hickory Clays, this ball clay is similar to Al2O3 .. and high-fire porcelains. Mined in Virginia. Foundry Hill Cream. Extremely plastic. TiO2 .. SiO2 .. SiO2 .. Al2O3 .. Fe2O3 .. Al2O3 .. Fe2O3 ..94. CaO ..20. Fe2O3 .. MgO ..50 KNaO ..42. TiO2 .. K2O .. TiO2 ..67. CaO ..13 Na2O ..20 CaO ..03. MgO ..42 So3 ..16 MgO ..01. K2O .. C ..34. Na2O ..10 Nepheline Syenite (270 mesh). PCE.

9 A lower fluxing form of a soda spar. 5% potash, Kona F-4 (200 mesh) or soda. Mined in Ontario, Canada. Grog 20 coarse Minspar 4 (200 mesh) SiO2 .. Grog 35 medium These interchangeable feldspars are used wherever a soda Al2O3 .. Grog 50 fine spar is called for. Both are mined in North Carolina. Fe2O3 ..06. Ground and screened refractories, in our case ground up pot- potash, soda. CaO ..15. tery. Used to open up clay bodies, such as stonewares and SiO2 .. MgO ..02. raku. Strengthens, reduces shrinkage and adds texture. Al2O3 .. K2O .. Fe2O3 ..04 Na2O .. Grolleg China Clay (200 mesh). CaO .. Imported from England. One of the whitest kaolins avail- K2O .. Nickel Carbonate Green (Ni2CO3). able. Not very plastic. SiO2 .. Na2O .. Weaker form of nickel. Easier to mix. Fumes are toxic. Al2O3 .. Kyanite 48 (48 mesh) and Fe2O3.

10 07 Nickel Oxide Black (Ni2O3). Kyanite 100 (100 mesh). TiO2 ..03 Produces browns, grays, blues, yellows and greens. An alumina silicate mineral that can be used instead of and CaO ..10 with grog to strengthen clay bodies. Helps with thermal Maximum amount in glazes is about 3%. MgO ..30 shock in raku bodies. Toxic in raw form. K2O .. SiO2 .. Na2O ..10 OM4 Ball Clay (200 mesh). Al2O3 .. The most common midwest ball clay, mined in Kentucky. Fe2O3 .. PCE ..Cone 35 Very plastic and is used wherever a ball clay is called for i KNaO .. glaze or clay body. TiO2 .. SiO2 .. Hawthorn Bond (35 & 50 mesh). CaO ..50 Al2O3 .. A Missouri fireclay with similar properties to Green but MgO ..30. less expensive. Fires light buff at Cone 10. Fe2O3 .. SiO2 .. TiO2 .. Al2O3 .. Lithium Carbonate (Li2Co3) CaO ..01. Fe2O3.