Roky

they slaver men sayne - Lyke a roky rayne. - Skelton.

He […] in a roky hollow, belling, etc. Roky (associated with reek) means misty, foggy.

They walked around in the roky damp, in silence.

[…] scaly, and frightfully roky bar.

then elongate and “open-out,” producing “roky” billets and blooms. When the cracks are from top to bottom, i.e. longitudinal, it is usually because cooling, after the ingot has been taken out of the mould, has been uneven.