Feather edge

where harling is reduced to the thinnest possible coat, to give way to dressed stone, limewash etc. Also refers to reduced thickness in timber boards.
Found on http://www.encyclo.co.uk/local/20935

Feather Edge

A sharp arris formed by beveling or cutting a piece of stone
Found on http://www.selectstone.com/architectural-resources/stone-glossary/
No exact match found