ktfaber@caltech.edu1Controlled heterogeneous fracture through the splitting of micaThis is the dataset which produced the findings described in the paper: Obreimoff revisited: controlled heterogeneous fracture through the splitting of mica. Included are datasets of splitting force measurements for homogeneous mica sheets of varying splitting thicknesses, as well as heterogeneous mica sheets where the splitting thickness changes partway through the sheet. All testing was done on an Instron 5982 load frame.0Original Data1Data available in data repositoryMendeley Data http://dx.doi.org/10.17632/46x4nvr8zc.2 http://dx.doi.org/10.17632/46x4nvr8zc.2