This is a very unique terpene that is rarely found in cannabis flower, but always found in Moroccan style hash. Hashinene is a by-product of the unique and very simple hash production process used in Northern Africa, specifically the Rif Valley of Morocco.
Hashinene's full chemical name is 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane and was first isolated in 2014. Studies found that hashinene is actually an oxidative product of Myrcene that is the result of drying and curing a harvest on rooftops in the equatorial sun, as the Moroccans have done for many centuries. The heat and UV light catalyze the transformation. Hashinene has the same molecular formula as Myrcene, but with a "radically different" chemical structure.
This happens with terpenes, too. Most of the "secondary" terpenes in cannabis are actually just oxidative products (analogs) of the top 8 terpenes found in cannabis, including Myrcene, Pinene, Humulene, and Caryophyllene.
There is little research about possible medical benefits, but those that have experience know it's different. Thanks Hashinene! There is some CBD as well as Hashinene in most dark Moroccan hash.