Perlite is a rock that forms when lava cools very rapidly (volcanic glass). Once the volcanic glass is mined, it goes through a manufacturing process that heats the raw material causing it to expand. Commercial perlite is commonly used in potting soils to offer natural aeration without compacting soil media. Perlite is also used construction materials like insulation, and masonry blocks.
Perlite is porous and retains water making it a versatile incubation substrate for all reptile species. Perlite should be premixed with water before use when incubating. One of the challenges with perlite, compared to vermiculite, is that it can be harder to get the right level of moisture. Beads of perlite stay relatively firm in both dry and wet forms.