Brazil nuts are actually the seed (not a true nut) of a tree that grows in the Amazon. The seeds are grouped in clusters within a hard, coconut shaped shell. Brazil nuts are very high in selenium. The shells are harder than other nuts so be prepared with a sturdy nut cracker or you may have to resort to using a hammer.
Find Brazil nuts in your local grocery store or online at Nuts.com as well as other sources. Brazil nuts can be purchased in their shell or shelled. This nut has a high-fat content and is prone to rancidity so don't plan to store them in the pantry for a very long time. You can shell the nuts and freeze them for longer storage life.
There are some good options if you need a substitute for Brazil nuts:
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