Exo Terra Desert Sand. Exo Terra's Desert Terrarium Sand is natural real desert sand with no added dyes or chemicals. The sand has been sifted to remove impurities and to obtain a homogenous sand grain size. Natural desert sand, no added dyes or chemicals Creates a natural and attractive desert environment Excellent heat conductor Stimulates natural digging and burrowing behavior Suitable as egg-laying substrate The Desert Sand comes in 4.5 kg (10 lbs) bag, and is available in Black, Yellow and Red.