Mastic is a type of resin which is collected from the tree of the same name. The island of Chios in Greece is particularly famous for its mastic production, although the resin is also harvested in other regions of the Mediterranean. Middle Easterners and Greeks have been using it for centuries in a variety of applications ranging from cosmetics to chewing gum. Many people who experiment with recipes from these regions have probably also noticed that mastic is used as a spice in many traditional foods.
The mastic tree or Pistacia lentiscus is an evergreen tree which produces distinctive red berries. In the mid to late summer, producers slit the bark to encourage the tree to start secreting resin. The resin trickles out slowly, creating small blobs with a vaguely crystalline appearance. Some people call these chunks “Chios tears” in a reference to the fact that they look like tears and they are harvested on Chios. One a tree has stopped secreting resin, it is collected and prepared for sale.
Typically, mastic granules are sold whole, and consumers must grind them down if they require powder. Ground, it is used in a variety of baked goods for its rich, resinous aroma and licorice-like flavor. It is also used to flavor alcoholic drinks in some parts of the Middle East. Ground mastic can also be used in cosmetics and various resin products like varnish. Some consumers skip the refinement process and simply chew the crystals, which have a very resilient texture.
Mastic chewing isn't just recreational. The Greeks have been chewing on resin granules or young branches for centuries, as visitors to the region have often noted. Mastic was consumed to freshen the breath with its pleasant odor, but scientific research suggests that it also cuts down on bacteria in the mouth, and that it can remove dental plaque. The resin also appears to have antifungal properties.
Outside of Greece and the Middle East, it is sometimes possible to find whole crystals. Some specialty stores also sell it ground as a spice, or mastic-flavored chewing gum for people who want to enjoy the health benefits and sweet scent. In regions without a sizeable Greek or Middle Eastern community, it can be challenging to find, but you should be able to order it through retailers who are willing to ship this plant product.