It's a brick. Soft, lightweight, just what I wanted for my diy forge. Forge is a 6" dia. steel pipe so a whole brick would be a bit too thick, so the softness of this brick made it easy to cut in half. Used a hack saw, cuts very easily. My forge is 12" long so I had enough brick to line the full length of the bottom. It glows red when running the forge but doesn't seem to hurt it

Really light

Brick came broken. It is very very fragile. My friend's bricks are much more sturdy. Not happy with the quality at all, not at all.

I am very new to metal work. One thing I don't want to do is set my table on fire! I have started doing a little soldering with my creme brulee torch had read the suggestion online or in a book to use a ceramic fire brick underneath a magnesia brick for extra heat protection for your work surface, so that is why I got this. (I put all of this on top of an old cookie sheet lined with foil.)

I don't work with very large pieces, mostly bracelet-sized and some practice square projects from a soldering book I bought. So far I have only been using copper. But this is sufficient for what I am doing. The heat honestly doesn't reach through the magnesia block to this one, so this is still in good shape and I will probably just start working directly on this once my magnesia block crumbles to bits.

There is not much else to say about a ceramic brick! This has a rough surface so your work won't slide around if you are working directly on this block. And it is an excellent insulator. Since I am a beginner, I am still deciding on my preferred set-up but I am happy I bought this and would gladly do so again if I had it to do over.

As described, quick shipping