| Citation | He is the leading person in the world in bringing ideas and techniques of modern solid state physics and chemistry to bear on a broad range of mineral transformation behaviour. The most significant contribution has been to the understanding of ordering transformations in minerals, particularly the origin of incommensurate modulated structures, with the application of group theory and symmetry principles generally. He is now applying these ideas to understanding premartensitic behaviour. His pioneering application of electron microscopy to mineralogy led to the first identification of antiphase structure, spinodal behaviour and other effects in feldspars, sulphides, pyroxenes and oxides, work summarised in the first (1971) Hallimond Lecture to the Mineralogical Society. His early work on interpreting transformation kinetics showed how the kinetics gave evidence of the transformation mechanism. Thermodynamic studies initiated by him have shown that incommensurate modulated structures are nearly as well ordered as the pure end member structures. Recent work at Schlumberger Cambridge Research is elucidating chemical, physical, microstructural and mechanical properties of shales, as well as the mechanism of migration of hydrocarbons in shales as source rocks for oil. His graduate text Principles of Mineral Behaviour is in worldwide use, as are several published lectures from Nato Summer Schools. |