Cone 4 #31 Opaque/Satiné

Custer feldspar 52
Whiting 5
Zinc oxide (Calc.) 9
Barium carbonate 11
Strontium carbonate 8
EPK 5
Silica 10
Total 100

Na2O 0.07 Al2O3 0.31 SiO2 2.30
K2O 0.16 P2O5 0.00
MgO 0.00 TiO2 0.00
CaO 0.15 Fe2O3 0.00
ZnO 0.31
SrO 0.15
BaO 0.16

Alumina:Silica ratio is 1.00:7.44
Neutral:Acid ratio is 1.00:7.46
Alk:Neut:Acid ratio is 1.00:0.31:2.30

Expansion: 86.6 x 10e-7 per degree C
Oxides causing abnormal expansion: SrO