That would depend on the particular species of Boswellia you prefer. The Middle Eastern B. sacra, the Indian B. caterii, the African B. frereana, or some other species. Each source of frankincense (from each species) produces varying degrees of quality. You can do Google search, for example:
boswellia sacra essential oil
then hit 'shopping' button, and be directed to the various suppliers of that particular form of frankincense.