Are you wondering what resins are? Well, here is a simple explaination from Aroma Web:
"When some plants, namely trees, are injured, they produce a thick, sometimes solid, sticky substance called a resin. Benzoin (Styrax benzoin) is an example of a resin. In commercial production, the trees will be cut in many spots to encourage the tree to produce its resin.
Natural resins provide therapeutic benefit, but some are hard to work with in aromatherapy because they are extremely thick and sticky. You will find liquid resins that have been extracted by solvent or alcohol extraction.
Frankincense tears is another example of a resin. Frankincense tears are small, solid chunks of frankincense resin. Frankincense tears are most commonly used in oil infusions and in making incense."