Canada Balsam is the pale yellow oleoresin with a faint greenish cast of the balsam fir tree. It dries to a clear transparent film and it is amorphous when dried. Since it does not crystallize with age, its optical properties do not deteriorate.

Canada balsam is used as a plasticizer for varnish and paint and can be used as a varnish when diluted with a small quantity of denatured alcohol, lavender spike oil, or spirits of gum turpentine. The resin can be mixed with drying oils (such as linseed and walnut oil), and with other resins (such as copal and damar) dissolved in compatible solvents.

Canada balsam is used to prepare microscope slides and high precision optical lens assemblies. Balsam fir gum is used for optical lenses because, when dissolved in an equal volume of xylene, its refractive index is almost exactly the same as that of glass.