Alternate Names: Isinglass, Muscovite, Biotite, Phlogopite
Clay-making mineral of the group mica (illite, glauconite, celadonite, etc.), a hydrous aluminum disilicate normally made up of Al, Si, K, Mg, Fe and Li plus traces of other metals. Can be used as a sort of catch-all mixture of recipe ingredients much as ash can be used, though not for the same or even similar composition, nor does mica absorb water as does an ash; and especially for increasing plasticity. Particularly when added to glaze slurries, a flocculant can hold the mica in suspension
for better mixing.
see aventurine, muscovite and schist
Muscovite Star Mica
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.
|Materials||Georgia Industrial Minerals Mica|
Raw ceramic materials are minerals or mixtures of minerals. By taking the characteristics of these into account technicians can rationalize the application of glaze chemistry.
Mica at Wikipedia
Generic materials are those with no brand name. Normally they are theoretical, the chemistry portrays what a specimen would be if it had no contamination. Generic materials are helpful in educational situations where students need to study material theory (later they graduate to dealing with real world materials). They are also helpful where the chemistry of an actual material is not known. Often the accuracy of calculations is sufficient using generic materials.