Incense is a product of aromatic plant matter, often with an oil or resin as a base. In the Orthodox Christian practice, incense is an important liturgical implement which is often considered distinctive to the Faith as well.
Incense is burned in a gold censer and ignited by burning charcoal. Customarily, the censer is suspended by chains and swung; however, a hand censer can be used when necessary. The censer is employed only by the priest and/or deacon to venerate all four sides of the altar, the Holy Gifts, the clergy, the congregation, icons, and the church structure itself. (Orthodox Wiki)