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M2 Red Stoneware

Alternate Names: Plainsman M2

Description: Medium temperature deep red burning stoneware

Oxide Analysis Formula
Fe2O3 6.10% 0.29
SiO2 69.40% 8.72
P2O5 0.30% 0.02
Al2O3 13.50% 1.00
TiO2 0.70% 0.07
Na2O 0.10% 0.01
MgO 1.00% 0.19
K2O 2.70% 0.22
CaO 0.30% 0.04
LOI 6.00%n/a
Oxide Weight 710.98
Formula Weight 756.36


M2 is a red burning low to medium temperature stoneware clay. It can be used as-is for many applications requiring deep natural fired color. It has about the right plasticity for plastic machine forming (slightly less than for hand modelling). It burns to an attractive dark red at cone 3-4 and by cone 6 it turns dark brown. At cone 2 it fires to a warm red progressing down to a typical terra cotta color at cone 06-04. M2 is quite similar to Redart but it is more plastic.

See the data sheet and (link below) for more information on properties.

Related Information

M2 vs. Redart

Plainsman M2 (left) vs. Redart (right). These bars are fired cone 04, 02, 2, 3, 4 (top to bottom). Fired color is almost identical. M2 has a little more soluble salts (however M2 has no chemical additions to precipitate them, it is ground as the pure mined material). M2 is more plastic (although still not as plastic as a typical pottery clay). However, Redart will make a good casting slip while M2 does not respond to deflocculants.

Plainsman M2 clay (right) and a terra cotta (L215 left) fired to cone 04,02,2 and 4.

Raw red burning clay stockpile

The raw Plainsman M2 clay stockpile before it is ground. This is mined in Montana and imparts red color to various middle and low temperature clay bodies. It is a remarkably consistent material.


M2 Data Sheet
Materials Saint Rose Red
Materials Redstone
Materials Plainsman Red Fireclay
Materials Fire-Red
Typecodes Clay Other
Clays that are not kaolins, ball clays or bentonites. For example, stoneware clays are mixtures of all of the above plus quartz, feldspar, mica and other minerals. There are also many clays that have high plasticity like bentonite but are much different mineralogically.
By Tony Hansen
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