I think we can deduce the general rule about this from the case of sesame seeds. They are not normally eaten by themselves - at the very least they are together with honey (ie sesame bars), and the brocha is haadama in such a case (unless they become tafel to something else). Yet, they still 'retain' the bracha of haadama even in the unusual case of being eaten by themselves (see What bracha should one make when eating raw sesame seeds?What bracha should one make when eating raw sesame seeds?).