The expression “stamp collecting” is commonly used in a derogatory way for study areas that frequently rely on case studies and observations, sometimes resulting of chance, which can be perceived as akin to mere accumulation of facts without value for theories or as being only usable in a inductive perspective. However, even the main opponent of inductivism of the last century, Karl Popper, admitted in his “Realism and the aim of Science” that “some [scientists] may get their ideas by observing, or by repeating observations” (albeit this was put in the same level of getting ideas from smoking or drinking coffee or whisky).

In Geosciences there is a long history of the relevance of case observations that can serve to refute models or as catalizers of ideas, namely for features that cannot be replicated under controlled experimental conditions.

This publication aims to present an overview of examples illustrating how case observations can contribute to Geology teaching, base in the author’s own experience concerning both rock outcrops and stones present in the built environment. The examples presented will concern diverse study areas namely Mineralogy, Geomorphology, Geochemistry, Petrology, Ore deposits, Engineering Geology and Mineral Exploration.

These case observations will be also used to highlight the importance of hypothesis discussion and critical thinking.