Masticha Chiou (Chios Mastic) is a unique, aromatic natural resin obtained exclusively from the mastic tree (Pistacia lentiscus var. Chia) on the Greek island of Chios. Known historically as the "Tears of Chios," this resin is excreted from incisions made in the tree's bark and solidifies into translucent, brittle teardrops. It holds a Protected Designation of Origin (PDO) status within the European Union, meaning only resin produced in the 24 specific "mastic villages" (Mastichochoria) in southern Chios can legally bear the name.