There are a few factors to consider when choosing a litter for your Siamese cat. Here are a few things to consider:

1. Dust levels: Some litters are more dusty than others, which can be a problem for cats with respiratory issues or allergies. If your cat has any respiratory problems, you may want to look for a litter that is low in dust.
2. Odor control: Some litters are better at controlling odors than others. If you have a multi-cat household, or if your cat’s litter box is located in a high traffic area, you may want to choose a litter that has good odor control.
3. Clumping vs non-clumping: Clumping litter is more convenient to use because it allows you to easily scoop out soiled litter, but it can be more expensive. Non-clumping litter is generally less expensive, but it may be less convenient to use because it requires you to completely change out the litter more frequently.
4. Natural vs synthetic: There are both natural and synthetic litters available on the market. Natural litters are made from materials such as corn, wheat, or pine, and are biodegradable. Synthetic litters are usually made from clay or crystal-based materials, and are not biodegradable.

Ultimately, the best litter for your Siamese cat will depend on your personal preference and your cat’s needs. It may be helpful to try out a few different types of litter to see which one your cat prefers.