Mike,
With your geological hat on have you come across this material before? If so what's your opinion of the validity of the claims thy make about it?
I encountered it yesterday at an Ecological Festival in Nicosia and once I got home I tried to find out more about it from the internet. I found all sorts of websites making wild claims about its uses in practically every field imaginable, Medicine, Agriculture, Water filtration, Animal husbandry, etc, etc. Below is just one of them.
In agriculture, clinoptilolite (a naturally occurring zeolite) is used as a soil treatment. It provides a source of slowly released potassium. If previously loaded with ammonium, the zeolite can serve a similar function in the slow release of nitrogen. Zeolites can also act as water moderators, in which they will absorb up to 55% of their weight in water and slowly release it under the plant's demand. This property can prevent root rot and moderate drought cycles. Clinoptilolite has also been added to chicken food, the absorption of water and ammonia by the zeolite made the birds droppings drier, less odoriferous and hence easier to handle.