Alternate Names: DakotaPure Mica
Available in various sizes. It is added to terra cotta clay bodies to create sparkles. Standard grades are much too fine for this effect, use the drilling mud grades (the flakes heal leaks the way platelets do in the blood stream). These are called LCM Drilling Mud Mica.
The analysis provided here does not add up to 100 and the manufacturer does not provide an LOI. The highest LOI we can find on a typical mica is 5%, so this was used. Either the other numbers need to be scaled up to total 95 or the LOI set to 10.0 to account for unspecified volatile materials.
An example of how a small addition of mica affects the fired appearance of a terra cotta clay. The effect is still working at cone 03 (left) but is more commonly employed at cone 06 (right). Notice that it is still visible even under the glaze. This body is popular on the west coast, it was designed by D'Arcy Margesson. Standard grades of mica are too fine for the effect, this is likely Custer LCM Drilling Mud Mica.
The Mica Group of Minerals
Mica at Wikipedia
Custer Drilling Mud Mica
Materials not classifiable as commonly known aluminum silicates. For example, kaolin is a common aluminum silicate.
|Bulk Density lbs/cu. ft. (Packed)||33.2-A200, 30.9 A-140|
|Bulk Density lbs/cu. ft. (Packed)||33.2|
|Sieve Analysis Dry||A200 Grade: +100: 0.3 +200: 20.4 +325: 35.3 A140 Grade: on 80#: 1.0% on 200#: 58.0%|
|Sieve Analysis Dry||+100: 0.3 +200: 20.4 +325: 35.3|
|Density (Specific Gravity)||2.66|
|pH for dry powder||8.0|