The α-β inversion in submilligram particles of natural quartz

The bacground to the supposed development of the ‘Beilby layer’ on fine-grinding quartz is briefly reviewed. It is shown, using single crucible thermal analysis and sub-milligram DTA, that grinding quartz can cause a dispersion of the α-β inversion over a temperature range of several degrees; this is a crystallographic effect rather than an impurity effect. The sub-milligram DTA apparatus used is described and some thermal effects, such as impurity zoning, are illustrated.