The deterioration of monumental stones is a common event occurring to our historical and cultural heritage, threatening the preservation of our social identity and its legacy to future generations. The prolonged effect of inclement weather is very harmful for particular stone materials such as limestone and dolomite, to which a truly effective and durable protective agent has not yet been found. Herein, an unprecedented performance of graphene oxide (GO) for the shielding of carbonated ornamental stones against environmental aggressions, namely intense rainfall and extreme temperatures, is demonstrated. A simple additive-free aqueous suspension of GO serves as the perfect coating, exceedingly preventing from any kind of wear or erosion after different climatic simulations. Additionally, the stones’ original aesthetics is not altered (a critical issue in monuments), together with an improvement in their mechanical properties, reasserting the unique potential of GO for conserving exposed stone-based monuments in an affordable, accessible, and revolutionary way.