The RRUFF database is proposing Raman spectra of natural samples. The natural Molybdenum Disulfide is given as a 2H-MoS2 crystal in the hexagonal phase. The material is a semiconductor, characterized by an indirect band gap of 1.2 eV (hqgraphene). The purity is enhanced in synthetic MoS2. "Monolayer MoS2 has a band gap of ~1.8 eV. … MoS2 belongs to the group-VI transition metal dichalcogenides (TMDC)" (hqgraphene).