The most important tool for geological field work is the geologist's hammer. It is used to strike the rock in order to create fresh fracture surfaces and thereby identify the coarse mineral composition, texture or fossil content of the rock or to obtain rock samples. In addition, a geologist's hammer is often used as a yardstick when taking photos in the field - this is also the reason why geologists have significantly more photos of their hammer than of family members!
The rock samples obtained with the hammer can be used for further investigations in the laboratory.