Brikar

The Brikar are a sapient species of burly bipeds with tough rock-like skin.

Biology
The Brikar are large humanoids with hard, stone-like skin. They're substantially stronger than Humans and invulnerable to most bladed weapons. In spite of their armoured skin, Brikar still need protection against the cold and need to wear environmental suits in space.

Appearances

 * Starfleet Academy: Worf's First Adventure, by Peter David (1993)