Its seed coat is hard and thick, you have to grind off the tip (germination point) a bit before soaking in water, this will ease and speed up the germination.
* p0 V% C z% Z/ q; ^* k' x, q
If you mean those from chinese groceries store, it may not be possible to germinate, I guess they are dried and the protective seed coat was peeled off. They are lifeless food stuff.