Mastic is the resin of the pistachio tree (Pistacia lentiscus), an evergreen shrub that belongs to the sumac family (Anacardiaceae). The shrub or small tree usually reaches heights of 1-3m, but can grow up to 8m. The bark and branches of the pistachio trees are cut open (scarification) to allow the resin to slowly pour out. This process happens annually in June.
The Pistacia lentiscus variety grows exclusively on the Greek island of Chios in the Aegean Sea. "Mastic" means the tears of Chios. The traditional cultivation of mastic gum has been included in the intangible cultural heritage of humanity by UNESCO since 2014.