[14]

In the article they referenced if you want a brick stronger then a 40% limestone brick you just have to let these bricks grow a little longer. So they can be at least as strong as a limestone brick if that is any sort of reference.

[viggity]

Limestone is a 3 on the Mohs scale (1 = talc, 10 = diamond).

A kiln fired brick is a 5 to 7 depending on its constituent parts.

[wulfmann]

What is a beet's strength on the mose scale?