If there was occasionally a certain hardness to this interpretation, it remained a performance of brilliance and force.

A certain hardness of outline may attest to his early training in metal work.

Art's face settled to a certain hardness that still was not hostile.

"As the population increases, a certain hardness of heart also creeps in," she said.

They wore nondescript clothes and had a certain hardness to their manner that Serena did not like.

"There are political considerations beyond my control," the President said, a certain hardness creeping into his voice.

Largely amateur choirs have a hard time escaping a certain hardness of sound, and this one couldn't either.

There's a certain hardness about her as a player.

A certain hardness in his eyes belied any real sorrow.

It is an indication of how deep into the material a certain hardness can be achieved.