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MC 200K Feldspar

Alternate Names: MC 200-K Feldspar

Description: Feldspar

Oxide Analysis Formula
CaO 0.20% 0.02
K2O 12.80% 0.84
Na2O 1.40% 0.14
Al2O3 18.10% 1.10
SiO2 64.20% 6.59
Fe2O3 0.06% -
LOI 0.56%n/a
Oxide Weight 597.19
Formula Weight 600.55


Consider this as an alternative to G200 as a 200 mesh feldspar. It is very clean and exceptionally low in iron (due to their froth flotation process). 325 and even 625 mesh versions are also available, they have the same chemistry.

The company says: MC 200-K Feldspar is a high quality potassium/sodium/calcium aluminum silicate ground to 200 mesh for ceramic applications. Carefully beneficiated and controlled for quality, MC 200-K Feldspar offers high potash and low iron oxide
content per unit of alumina.

Related Information

Feldspars, the primary high temperature flux, melt less than you think.

Tap picture for full size and resolution

A cone 8 comparative flow tests of Custer, G-200 and i-minerals high soda and high potassium feldspars. Notice how little the pure materials are moving (bottom), even though they are fired to cone 11. In addition, the sodium feldspars move better than the potassium ones. But feldspars do their real fluxing work when they can interact with other materials. Notice how well they flow with only 10% frit added (top), even though they are being fired three cones lower.


Typecodes Feldspar
The most common source of fluxes for high and medium temperature glazes and bodies.
Materials Custer Feldspar
The most common potash feldspar used in ceramics in North America. While having been a standard for many decades its supply appears in doubt in 2024.
Materials G-200 Feldspar
I-minerals feldspar data sheets
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