The invention provides a method and apparatus for the analysis of rocks and rock fragments. A method for the analysis of a rock fragment including: feeding the rock fragment to a microwave irradiation zone of microwave energy generated by a microwave source; gauging energy absorbed by the rock fragment; and correlating rate of change of the gauged energy absorbed by the rock fragment with compositional characteristics of the rock fragment. The rock fragment analysis assembly including: a microwave energy source that generates a microwave irradiation zone; a rock fragment feed that facilitates the feeding of rock fragments into the microwave irradiation zone; at least one primary sensor located on a microwave energy source side of the microwave irradiation zone for gauging microwave energy absorbed by the rock fragments in the microwave irradiation zone; and a processing unit for correlating rate of change of the gauged energy 26 absorbed by the rock fragments with compositional characteristics of the rock fragments.