You both want an absorbent substance in which your feline companion will eliminate. And odor control is high on both of your lists. However, what smells good to you may not smell so good to your cat. Also, for you, cost may be an influencing factor. So you'll probably want to do some comparative pricing.
Any absorbent substance can function as a cat-box filler.
This type of litter does not contain gravel, as its descriptor implies. On the contrary, like its sandlike counterpart, it is merely natural, dried clay. Not all clays are suited to become litter, however. Manufacturers mine, dry, and grind to size only the more absorbent clays. Manufacturers often add a dust-controlling agent to the ground clay to prevent the dust from becoming airborne.