A high iron, slightly sandy, medium plasticity, refractory, deep red burning raw clay material. Ideal as a source of iron in high fire iron-red reduction bodies. Although not a fireclay, this material is refractory enough to withstand cone 10 and still be relatively porous.

The two high-iron ingredient clays in Fire-Red.

Fire-Red is a blend of three high iron clays. About half of the mix is a refractory low plasticity bright red material mined in St. Rose, Manitoba. One third is a medium plastic maroon clay from Montana (M2). The remainder is a bentonitic, pyritic brown clay from Saskatchewan (A1).

Fire-Red is an excellent addition to high temperature clay bodies to darken their fired color. It will have minimal effect on plasticity and it will not flux the body (making it too vitreous). It contains natural iron pyrite particles that impart attractive speckling in reduction firing.

Fire-Red is the basis for the red colors of Plainsman H440 and H440G and of the brown in H443.

Fire-Red thrown surface. 10 inch bellied vase.

Substitutes For

Newman Red clay.


These are six different runs of FireRed. The top bar on each is cone 10R, the next one down in 10 oxidation. The third one down is cone 8 (where the red color is holding).

Fire-Red is refractory compared to other high-iron raw materials. It fires deep red in oxidation (cone 8) and metallic chocolate to black in reduction.

To achieve classic iron reduction variegation in bodies using this material it is necessary that they do not fully vitrify at the target temperature. Typically 2-3% porosity or higher will give an attractive earthy warm coloration and texture (use caution when using for functional ware, glazes should be fitted well with a minimum of exposed unglazed clay).


The dominant contribution of Fire-Red is fired speckle and dark iron color, especially in reduction firing. It works well with glazes that enhance the speckle and those into which the body iron can diffuse.

Physical Properties

 Drying Shrinkage: 5.5-6.5%
 Dry Strength: n/a
 Drying Factor: C130

Sieve Analysis (Tyler mesh):

     +48: 0.5-1.0%
   48-65: 2.0-4.0
  65-100: 3.0-5.0
 100-150: 4.0-6.0
 150-200: 5.0-7.0
 200-325: 6.0-8.0

Fired Shrinkage:

   Cone 6: 3.5-4.5
   Cone 8: 4.0-5.0
  Cone 10: 4.5-5.5
 Cone 10R: 4.0-5.0

Fired Absorption:

   Cone 6: 8.0-10.0
   Cone 8: 6.5-8.5
  Cone 10: 5.0-7.0
 Cone 10R: 2.0-3.0

Chemical Analysis

 BaO       0.3
 CaO       0.5
 K2O       1.1
 MgO       0.6
 Na2O      0.1
 TiO2      0.9
 Al2O3    15.4
 P2O5      0.2
 SiO2     66.3
 Fe2O3     6.9
 MnO       0.1
 LOI       7.6%


Fire-Red vase with G2571A bamboo glaze - cone 10R

Safety Data Sheet

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Logo Plainsman Clays Ltd.
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508