Over the years I've used them all. Clumping, non-clumping, scented, unscented, multi-cat, crystals, the list goes on and on.
Crystal Litter does sound attractive - It looks nice, it absorbs liquids quickly. You need less of it than Clay. The downside is that it is more expensive, can pose health risks if ingested, some cats do not like walking on it and like clay litters is not good for the environment.
But overall
Clay clumping litters seem to be the most popular form of cat litter. Due to the following reasons:
1. Most conveniently available
2. It's cheap
3. It has decent performance and cats will use it
4. Most owners are unaware of the dangers both to the cat and the environment.
I personally do not like using clay litter because the dust, smell, tracking, potential health risks but most importantly for environmental reasons.
Clay based litter must be mined and in the US 2.54 million tons of clay are mined each year. The process of mining creates has many environmental impacts. Then there is the disposal of this litter each year. Clay litter will sit in the landfill for an entirety as it is non-deogradable. It is estimated that about 4 million tons of clay litter enter US landfills each year.
