If you're looking for a high-quality insulation material that is also environmentally friendly, perlite should be at the top of your list. Perlite is a volcanic glass that has been heated until it pops like popcorn, creating countless air pockets that make it an excellent insulator. https://www.zupyak.com/p/31705....42/t/everything-you-

Cryogenic perlite is a volcanic material that is heated until it turns into a glass-like state. It is then cooled rapidly, which causes it to pop and create small, air-filled bubbles. https://amolminechemltd.medium.....com/what-is-cryogen