Cassia is one of the most popular ingredients in incense, perhaps the vast majority of people are attracted to the incenses that containes cassia. It seems to go beyond just being a pleasant aroma. There is a wide spectrum of quality and properties if cassia, from limb bark, to trunk bark, varying qualities and contents of oil, etc. Cassia, Chinese cinnamon, C. cassia, Cinamomum aromaticum, is the common household-spice most of us call Cinnamon. True cinnamon was replaced in the USA by Cassia during WWII. Mexico and Europe still use true Cinnamon for cooking.Another variety is Vietnamese Cinnamon ( Cinnamomum loureirii Nees.) which grows in Nothern Vietnam, and is actually a variety of Cassia despite the name.Cassia hails from Burma instead of Cinnamon's birthplace of Sri Lanka. A long used spice, cassia was used in China as long ago as 2500 BC
This is true cinnamon, which most people would not recognize as cinnamon.
Both cassia and cinnamon contain some amazing phytochemicals and share a great deal of these phytochemicals, however, some of the phytochemicals are in different plant parts. This makes it even more confusing. For example, eugenol is found in both, it is also found in clove. However, it is not found in the cassia bark, and only in low concentrations in the leaves. Both cinnamon and cassia are used in making Japanese incense. In our estimation cinnamon has similar properties to clove, but also very similar to cassia as well. Of course, there are differences also. You can see some of these differences in the phytochemical properties as listed below.
Cinnamaldehyde is in much greater concentrations in cinnamon than in cassia:
Cinnamomum verum J. PRESL -- Ceylon Cinnamon, Cinnamon; 6,000 - 30,000 ppm in Bark
Cinnamomum aromaticum NEES -- Cassia; 1,400 - 1,900 ppm in Bark
Ascorbic-Acid is found in Cassia bark and Cinnamon bark in low concentrations about equally (309 PPM)