Must useful glazes always fall within the parameters prescribed in limit formulae tables?

Unit 5 Topic 5
The Unity Formula

Definitely not. Limit formulae describe glazes which are generally balanced in terms of flux to alumina and silica. There are many fine decorative glazes which fall outside these limits.

Glazes which have unity formulae falling within the limit formulae parameters for the temperature at which they are to be fired, will have no excessive overloads of any particular oxide and should fuse to form stable glazes. They will be most likely all be'middle of the road' glazes which have a high durability, are generally shiny
and have little if any movement.

There are an infinite number of beautiful glazes which fall outside the standard oxide limits.

These glazes should not be used for the inside of domestic pottery and may not be appropriate for the outside of pots used for functional purposes.

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