Some case studies are presented ranging from geological fakes and frauds, homicides and one environmental forensic case. Fakes may be true geological materials such as created fossils or gems and precious stones, or where geological methods are used to analyse fakes, such as the stones or ceramics used in making archaeological or art forgeries (e.g., mineral pigments in paintings). Fakes have also been created for reasons of academic rivalry, career advancement and religious belief. Fraud commonly involves over-stated claims of ore content associated with mining and the oil and gas industry. The range of geological fakes, the uses of geological methods in detecting fakes, and the extent of fraud in the mining sector are all extensive and sometimes incredible. The homicide is case presented to demonstrate how the types of geological investigation described in the rest of this volume may be applied. We include an environmental forensic case for similar reasons, to show that forensic geology may be applied to more than homicides and fakery.