KYAN
An aluminium silicate that grows as long bladed crystals · A refractory, low-expansion aggregate in a clay body · It holds shrinkage down and opens the body · Most of it is still kyanite when the kiln goes off
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Kyanite is an aluminium silicate that grows as long bladed crystals. In a clay body it works as a refractory, low-expansion aggregate, holding shrinkage down.
Kyanite goes into a clay body rather than a glaze, where its blades sit in the matrix as a refractory aggregate and hold shrinkage down. It does turn into mullite, but not at any temperature a studio kiln reaches: the conversion begins around 1250°C and needs a good deal more than that, and time held there, to come anywhere near completion. Cone 6 sits below where it starts and cone 10 only just above, so in a studio body most of the kyanite is still kyanite when the kiln goes off. What it gives is what the mineral itself is — low expansion, refractory, and bladed rather than granular.
