ahylognosia

a·hy·log·no·si·a

(ā-hī-log-nō'sē-ă),
Inability to recognize differences in density, weight, and coarseness.
[G. a- priv. + hylē, matter, + gnōsis, recognition]

Ahylognosia

(1) The inability to recognise the density of a material—e.g., wood, metal, liquid, etc.
(2) A virtually extinct term for the inability to recognise the surface characteristics of objects. “Tactile agnosia” is a viable substitute.