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| The acicular nature of Wollastonite's crystals |
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| 50/50 Base Neph Sye - 50 Wollastonite - 50 |
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| 50/50 Base + Copper Neph Sye - 50 Wollastonite - 50 --------------------- Copper Carb - 2% |
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| Shorn Base + Copper Wollastonite - 25 Spodumene - 25 Cornwall Stone - 25 Talc - 25 --------------------- Copper Carb - 4% |
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| Shorn Base + Cobalt Wollastonite - 25 Spodumene - 25 Cornwall Stone - 25 Talc - 25 --------------------- Cobalt Carb - 2% Copper Carb - 1% |
1. The crystaline structure of Wollastonite can produce visible crystals in a fired glaze, seen in the Shorn glazes (below right), when the base glaze is low in alumina - the higher alumina will stiffen the glaze melt in such a way that the crystals cannot form
2. The crystaline structure of Wollastonite holds onto itself allowing the dry material to be lifted fingers down, in the same way that straw can be lifted fingers down
3. The fibrous form of Wollstonite is a good additive in low fire clay bodies because it promotes low thermal expansion and reduces drying and firing shrinkage
4. Wollastonite is an excellent source of Calcium - a strong flux - for glazes that does not bubble during the firing due to off gassing whereas Whiting, the other prominent source of CaO, produces bubbles in the glaze from off gassing
