Re: spodumene concentrate from Greenbushes mine in Western Australia. I fired a bowl half full of the spodumene sand to about cone 7. This is a guesstimate, because although Cone 9 was down, the bottom shelf was seriously underfired. The spodumene in the bowl puffed up to twice its volume and developed deep cracks in its surface. The pile which had been sand was now flour, no grinding required.
I have read in a couple of books that lithium glass does not have a negative co-efficient of thermal expansion. Only the crystalline forms do. But the same books say that up to about .09 of mole, lithium oxide does help cure crazing. More has the opposite effect.