I have small gravel, aquarium gravel. So mixing in a 1/3 rd gravel, 1/3 rd perlite to the cactus soil mix, would the lithops like this?
Sounds great to me! Depending on how they arrive, you might be able to see what kind of soil they're in. If they have more inorganic matter than what you've made, add some more perlite. If it's more organic, then add some more cactus mix