I have no idea if the grocery store ones will (have they been treated in some way???) but here is something...

"The seed of the Brazil nut may take 12-36 months to germinate and even then only attain 60% germination. Figueiredo et al. (1980) and Frazão et al. (1984) used physical and chemical method. to scarify the seed and enhance germination. Some of these worked, but not well. Finally they simply removed the shell (after soaking for 24 hours in water), treated the seed with fungicide for 60-90 minutes and sowed the seed in sand or sawdust germination beds. Germination starts within one month and after 6 months attains 80%."

and this

" * Posted by Baci z10Ca (My Page) on
Sat, Feb 5, 05 at 23:04

Someone mentioned store bought nuts. I have seedlings of walnuts, pecans, almonds, & pistachio trees from store bought seeds. On that coconut look for an sprout around the active eye."

Now you've got me interested. I just dug up 3 little walnut seedlings in my yard and put them in containers. Maybe i'll plant them @ my brother's house, since i've got no room for 100ft trees :)

The brazil seeds would certainly have been treated before being allowed into the UK. If only fumigated, they might still be viable, but if irradiated then your chances of germinating them would be virtually nil--even if you had the warm climate/heated greenhouse they need to germinate and grow. (Franktank: the nuts you successfully germinated almost certainly were grown in your own country and therefore not irradiated before being delivered to your greengrocer/supermarket.)