Although this Montana talc (Silverline 303) is white as a raw material (vs. dark grey for the Texas material, Natural Minerals C-98), it does not fire nearly as white (even thought their data sheets both claim 0.5% Fe2O3). The Montana material is still suitable in glazes (since low percentages are common) and in bodies as a flux (where 1-3% is all that is used). But in bodies where talc was employed to adjust thermal expansion, as much as 50% is used, this is not suitable for that.
|Materials||Natural Talc C-98|
|Materials||Silverline 303 Talc|