In pottery, leather-hard is the condition of a clay or clay body when it has been partially dried to the point where all shrinkage has been completed, and it has a consistency similar to leather of the same thickness as the clay. At this stage, the clay object has approximately 15% moisture content. The clay is still visibly damp (normally a darkish grey, if it began whiteish) but has dried enough to be able to be handled without deformation. The body is able to be gouged or incised without breaking.

(“Leather-Hard” 2020)

Bibliography

“Leather-Hard.” 2020. Wikipedia, December. https://en.wikipedia.org/w/index.php?title=Leather-hard&oldid=991801984.