Extrinsic and intrinsic strength of amorphous olivine films. Nanoscale amorphous olivine (a-olivine) intracrystalline layers, which can form in olivine polycrystals under high stress, has the potential to influence the mechanical properties of the rock in the vicinity of the brittle-ductile transition. It is therefore essential to determine the mechanical properties, in particular the strength, of these a-olivine films. To this end, we investigate the tensile deformation and fracture of a-olivine thin films deposited on a polymer substrate. Typical brittle fracture in form of numerous, long, straight, and parallel to each other cracks is observed during a tensile test. By using in-situ measurements of electrical resistance, the critical strain required for the generation of the first cracks was measured at 0.8 %. A combination of in-situ straining with optical microscopy and subsequent digital image correlation enables direct measurements of local strains within the unfractured film regions. It is demonstrated that a-olivine can withstand tensile strains of at least 2 %, which leads to an estimated intrinsic strength of 1.8 GPa. The results presented should contribute to a more comprehensive understanding of the mechanical behavior of olivine-rich rocks affected by grain boundary amorphization.