This was first recommended to us by an FHL member, Gail.
 
We find that one of our ferrets doesn't like it alone so we tend to mix
it with a pelleted litter.
 
This stuff is INCREDIBLE for odor control and marvelously clean, plus
if you live in an area where mold sets up in just hours at times (which
happens here in certain seasons) you will be very happy to know that
using enough of this litter in the mix has eliminated the mold allergy
problem Steve would at times get from litter.
 
(We still have to closely watch things like the toilet tanks, windows,
etc., of course.  Oh, a tip about black molds -- we learned on a site
devoted to them that the most dangerous ones do not like plain old soap
which is why the black molds which can start in in showers tend to be
not as much of a problem, so we run a streak of soap along the edges of
window panes and it has really reduced to frequency of the growth.)
 
Here is the manufacturer's site:
http://www.huntclubinc.com/html/default.asp
 
Here is the deodorizer used in it:
http://mineral.galleries.com/minerals/silicate/clinopti/clinopti.htm
Which begins:
>THE MINERAL CLINOPTILOLITE
> Chemistry: (Na, K, Ca)2 - 3Al3(Al, Si)2Si13O36-12H2O, Hydrated
>             Sodium Potassium Calcium Aluminum Silicate
> Class: Silicates
> Subclass: Tectosilicates
> Group: Zeolites
> Zeolite Family: Heulandite
> Uses: As a chemical filter, chemical absorber, water purifier and as
> mineral specimens.
> Specimens
 
and continues:
 
> Clinoptilolite is used in many applications such as a chemical sieve,
> a gas absorber, a feed additive, a food additive, an odor control agent
> and as a water filter for municipal and residential drinking water and
> aquariums.  Clinoptilolite is well suited for these applications due to
> its large amount of pore space, high resistance to extreme temperatures
> and chemically neutral basic structure...
 
See those sites and elsewhere for more info.
 
We buy it through Agway and get a LOT for a bit less than the price of
the an equivalent weight of processed wood pellet litters, but the
volume is much, much larger so a bag lasts much longer.
 
We have tried a LOT of things over the years and are extremely pleased
with this litter for mold control, odor control, lack of mess, and cost.
I gather that there is a kraft (i.e. cardboard pieces) version which is
larger for use in stalls (and may be what folks have recently been
discussing but I have been too busy to more than skim those posts)
which is even cheaper but must be purchased in larger volumes.
[Posted in FML issue 4846]