This is a seed that a friend got from a herbalist in Peru 25 years ago. The seed under the shell is edible - it tastes very sweet, and like artifical sweetener, then becomes extremely bitter. Both the sweetness and bitterness taste like artifical flavours. Those taking it are advised not to drink water for ten minutes after because it can reactivate the bitter flavour. It apparently has properties that cleanse the liver very effectively, as it stimulates enzyme and hormone production that causes the liver to flush itself. It best not to take them more than once a week.
When the shell is peeled off, it reveals a white, round seed with a pith-like texture. It has a texture similar to a unroasted peanut - neither crunchy nor soft.
That is everything I know about it.
Thank you for your help.