Clay Perlite properties?

I have read on here about some of you building your riser with perlite clay, even saying it can be reused in a rebuild.

So, that makes me wonder what is the finished perlite clay like, if it can be reused? Does the clay basically get fired to make a cast hard material, like fired bricks? Is it crumbly?@

The reason I  am asking is that I'm wondering if it can be used to make a lightweight brick for a project I'm needing to do. These bricks would be used for a small pit root cellar, maybe 3x3 feet square.

The reason Im interested in using perlite is so that they would be lightweight and therefore more easily moved and reused.

Hi, I'm in the first steps of getting my rmh off the ground so can't comment on the properties of pre fired clay but for your purposes could you just try setting it up with some lime or cement? Might be less faff than repurposing  the material?