- Acts as a
flux above C.4 and tends to produce a late fluidity.
- Similar action
to calcium, barium, zinc and strontium oxides but is not interchangeable
for any one of them.
- A refractory
and opacifier at low temperatures.
- One of the
lowest coefficients of expansion - useful in reducing crazing.
- A very high
surface tension - can give viscous melts and soft, rounded edges
but can cause crawling faults.
- Can act as
an opacifier and matting agent in sufficient quantities.
CaMg(CO3)2 - also
brings CaO (contains about 44% MgCO3).
- Talc and
- also bring silica SiO2
- Will effect
colour development - with cobalt tends to give magentas and violets.
encourages more iron oxide from the body to enter the glaze.
- Late fluidity
is useful in underglazes which will boil through late in firing
- High surface
tension useful in creating lizard skin in a high magnesium overglaze.