A novel combined method for highly brittle materials, which provides an efficient and accurate insight into multi-scale fracture modeling, is proposed. In particular, physically-motivated molecular dynamics simulations are performed to predict crack propagation, in the nanoscale, and therewith determine material and other parameters required for the macroscale modeling under a phase-field continuum approach. The proposed computational approach, which does not require any empirical parameters, contributes towards an improved understanding of mechanics at all length-scale levels.