>[1202] jennamite mine owner -
>Jennamite is a naturally-occurring crystal found in the Earth
>Kingdom, generally around Omashu (though deposits can be found
>elsewhere). It combines properties of a mineral and sugar rock candy,
>both valuable and edible, and has the unique property of growing when
>exposed to a living being's bioelectric field. Nobody is quite sure
>how it does this. Due to the difficulties incurred by mining by hand,
>a productive mine can be a very lucrative operation if managed
>correctly. This mine owner, therefore, combines the properties of a
>diamond mine owner AND a sugar plantation owner!

How, when and why someone decided to try and eat a rock they just mined in order to see if it's edible is beyond me. :)
Although now that I think about it (and my memory fails me to remember specifics), wasn't there a scene in a movie/tv show about making rock soup?