Silica Cat Litter - Cat Info Detective

Silica Cat Litter

Skye Blake-updated, white background

Hi all you silica sleuths! Skye Blake here, finding fascinating facts about silica cat litter…

paw prints coming in from a distance

The information here is for general knowledge… always see your vet with questions about your cat’s individual needs. 

Who Is Skye Blake?

Skye Blake-updated, white background

Skye Blake, Cat Info Detective, is a curious cat researcher (not a veterinarian) who sniffs out expert, reliable sources about cats, studies their information, then passes it on to you! 

Sometimes there’s not enough evidence for easy answers, so Skye gives you all sides, explains the situation as thoroughly and clearly as possible, and links you to experts on each page.

Sources are given at the bottom of each page so you can do more snooping.

Brands are mentioned for your information only… I make no money from them.

What is Silica?

silica beads and packet

Silica litter consists of Type B silica xerogel white crystals.

They’re formed from sodium silicate sand mixed with oxygen and water.

The formation process creates a silica bead with many tiny holes or pockets.

sphynx cat looking in litter box-silica

The holes allow it to adsorb (not absorb) around 40 times its weight in liquid (see below for more explanation).

You’re probably familiar with these beads from the “Do Not Eat” packets you find in medications, shoes, electronics, and other products that need to stay dry.

The “Do Not Eat” sign on packets of silica gel refers to the packet itself. The silica itself is non-toxic.

curious cat

It’s important to know that when used in litter these beads are made to be safe for cats (without crystalline silicate, which can be harmful to cats).

Most silica litters are non-clumping because of the way they work, however, sometimes silica crystals are combined with sodium bentonite to create a clumping litter.

How Silica Crystal Litter Works

silica litter crystals

“…[S]ilica gel removes moisture by adsorption onto the surface of its numerous pores rather than by absorption into the bulk of the gel.”1“Silica Gel”, Wikipedia

“Adsorb can be termed as a process by which the liquid or gas is not absorbed but it only forms on the surface. Absorb is related to volume whereas adsorb is related to the surface.”2“Difference Between Adsorb and Absorb” (Emphasis added)

scooping white litter

Crystal litter adsorbs liquid immediately and traps it inside each bead.

This keeps the rest of the litter dry and traps odors well.

The moisture evaporates quickly and odor-causing molecules are trapped inside.

The beads keep adsorbing and last about a month for one cat.

white cat squatting in litter box - silica

Silica cat litter works best 2-3″ deep in the box so the pee doesn’t get to the bottom. At this depth the beads can effectively absorb it.

Scoop the poop every day and rake or stir the beads so moisture can evaporate from them.

This will keep the litter usable for quite a while until eventually you must dump and replace it.

scoop with silica litter crystals

Some brands of silica crystal litter are less dusty than others, also having the advantage of not sticking to paws for less tracking.

The crystals come in various sizes, the smaller being softer on paws and the larger being good to keep tracking down.

Some cats don’t like larger sizes because it’s hard and uncomfortable.

A Word About Pretty Litter

cat sniffing silica litter in box

Brands and products discussed on this page are for your information and convenience only… I make no money from them.

PrettyLitter is different from other silica cat litters because it has indicators that react if urine pH balance is off or if blood is present.

There are imitators, but Pretty Litter is still the standard for speciality silica litter.

black cat using litter box

Here’s what the manufacturer says… “Regularly check the color of the litter.

Shades of yellow to olive green are an indication of typical acidity and alkalinity levels.

If you notice any other colors, thoroughly mix the litter and monitor your cat’s PrettyLitter closely over the next 24 to 48 hours.”3

scoop with silica litter crystals

“If color change persists, you should consider consulting your Veterinarian.”4

The FAQ page at explains in more detail what each color indicates.

Here are some reviews of Pretty Litter…

“Pretty Litter Cat Litter Review (We Tested It for a Month)”, All About Cats, June 12, 2020
“PRETTY LITTER REVIEW, Sven and Robbie, December 5, 2022
“Pretty Litter Review”, Urban Mommy, November 9, 2019

Other Brands of Silica Litter

sand/silica litter

Some other brands of silica cat litter are Dr. Elsey’s, Alpha Paw, Fresh Step, and Frisco.

You can find these and other brands at pet stores, some grocery stores, and online suppliers like Chewy, PetSmart, Walmart, and Amazon.

Check descriptions and reviews carefully for any products you wish to buy.

Here’s a review of Fresh Step Crystals…

“Fresh Step Crystals Litter Review & Discussion of Silica Gel (Crystal) Litters”, Byromie, December 4, 2019
cat watching other cat in litter box

Curious about other types of cat litter and boxes? Discover more at “Supplies for Cats“.

Having trouble with your cat peeing or pooping outside the litter box?

Find some answers to fix the problem and clean up the mess at “Behavior“.


Sources used on this website are either primary or secondary.

Primary sources are always preferable and have the most reliable information because they’re original and directly referenced.

Scientific abstracts and data are good examples of primary sources.

Secondary sources are weaker because they usually consist of opinions or articles that give no sources of their own.

However, sometimes they refer to primary sources.

When I use secondary sources, most are those with some authority, such as veterinarian or cat behaviorist books and articles.

List of Sources


“Absorption”, Wikipedia

“Adsorption”, Wikipedia

“Best Cat Litter for Kittens”, by Mallory Crusta

“Difference Between Adsorb and Absorb”,

“How Cat Litter is Made”,


“Kitty Litter”, by Amanda Yarnell, Chemical & Engineering News, Volume 82 Issue 17, p. 26, What’s That Stuff?, Issue Date: April 26, 2004

“Non-Tech High Tech Litters the Landscape”, Andrew Kantor (2004-12-10), USA Today

“Silica Gel”, Wikipedia

“What Is In Cat Litter? Understanding Clay, Silica and Biodegradable Cat Litters”, by Lorie Huston, DVM, PetMD

“What Is Cat Litter Made Of?”, May 1, 2014, World’s Best Cat Litter

“Which Cat Litter to Use: Silica vs. Clay-Based”, by Chris Brownlow, Chewy, Dec. 27, 2017

Updated April 13, 2024

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