Single crystal WS2 for mechanical exfoliation. The crystal measure a minimum of 3mm x 3mm in lateral dimensions. The crystals are 2H phase. The Raman spectrum of bulk WS2 shows 2 prominent peaks: the in-plane E2g mode at ~352cm-1 and the out-of-plane A1g mode at ~420cm-1. These peaks are characteristic for hexagonally crystallized WS2. When exfoliated in monolayer, the two peaks come closer and there is a strong photoluminescence around 1.9eV.