From Seed to Seed:
Plant Science for K-8 Educators

Resins. Resins are water-insoluble substances found in the stems and roots of certain plants, notably pines. In the plant they likely serve as a deterrent to herbivores. Extracted resins are generally brittle, somewhat transparent, and lustrous. Various resins have been used throughout the ages as boat caulking and, because they are combustible, they were also common in torches. And the resin from pines is used to make turpentine. Most commercial resins are now synthetically produced.

Frankincense and myrrh are resins from different species of small trees or shrubs found on the Arabian peninsula. Both were highly valued articles of trade. The Egyptians used them in embalming, fumigation, and medicine. Today they are used as ceremonial incense.