Natural wollastonite mineral particles are long accicular crystals. These are lost during normal fine grinding. However if the parent rock is processed carefully it is possible to maintain the character of the crystal shape to produce a unique powder with unusual properties. A hand full of this powder can be squeezed slightly and turned upside down and little of it falls away!
Fibrous wollastonite can, for example, be added to clay bodies to impart significantly greater dry strength. However this normally works only for low fire bodies since the wollastonite will work as a flux at higher temperatures and it tends to contain fired speck producing particles.
Generic Material 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.