The new natural substrate Terradune from Caribsea features smooth grains prevent injury to your petsâ sensitive scales and skin. Chemical free, no dye, no paint, no color transfer, no sharp grains, this reptile substrate is easy to clean, and low in dust to combat respiratory and bacterial issues. Itâs uniform grains distribute heat naturally and gently. Ideal for basking and suitable for laying eggs. Ideal for most desert reptile species and arachnids (bearded dragon, leopard gecko, desert tortoise, uromastix).