It may never have crossed your mind: In the bags of mixed nuts in the shell, none of the nuts are cashews.
In fact, cashews are never sold in the shell — for a very good reason.
The cashew nut is actually a seed surrounded by a double shell. The shell contains oils related to the same chemical in poison ivy that causes skin rashes, according to The Nutcracker Museum. The toxic oils are easily roasted off, usually in outdoor settings since, like poison ivy, inhaling the burning oils causes severe lung irritation.
The toxic exterior of the cashew is not the only thing that makes it unique.
A cashew tree first flowers with a small, delicate green, then pink, five-petaled flower, less than an inch long. The cashew nut grows on the flower. Above the nut grows a juicy, pear-shaped, red or yellow pseudo-fruit up to four inches long. The cashew apple is popular in tropical countries where the cashew tree grows, but its waxy outer layer does contain skin irritants that must be steamed off then washed.
The cashew apple has never been suitable for export since its skin is easily damaged.
The evergreen cashew tree can grow up to 46 feet tall. The oldest and largest cashew tree in the world is found in Brazil. It covers an area of about 2 acres. The branches of the tree bend to the ground under an immense canopy of leaves. Each branch takes root where it touches the soil, making it difficult to see the main trunk of the tree. Thought to be about 1,000 years old, the ancient cashew tree produces about 60,000 fruits each year.