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F-4 Feldspar

Alternate Names: f4 feldspar, KONA F4 feldspar, Kona f-4 feldspar

Oxide Analysis Formula
CaO 1.70% 0.16
K2O 4.80% 0.26
Na2O 6.90% 0.58
SiO2 66.70% 5.76
Al2O3 19.60% 1.00
LOI 0.20%n/a
Oxide Weight 517.79
Formula Weight 518.83


Shipped from Spruce Pine, North Carolina. No longer available. Minspar 200 (formerly NC4) has virtually identical chemistry to F-4 and should be a good substitute.

Particle sizes:
+100 mesh: trace
+140: .1
+170: .1
+200: .2
+325: 3.8

This material is prized as a porcelain ingredient because of its low iron content. It is used in casting and throwing porcelains of all types. At cone 6 for example, it is possible to make a vitreous body using 50-60%. However to get enough plasticity in such bodies, it is necessary to use ball clay or bentonite which can darken the color. If high plasticity is not essential, Macaloid and plastic kaolins can be used.

Another similar material is Nepheline Syenite.

Related Information


Materials C-6 Feldspar
Materials Nepheline Syenite
Materials Minspar 200
Materials NC-4 Feldspar
Materials G-200 Feldspar
Typecodes Feldspar
The most common source of fluxes for high and medium temperature glazes and bodies.
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