Obsidian

Living deep in the Earth is Obsidian. A canine who has crystals growing out of his body.

He's an unusual and unique dog, having never come across another like him in his travels, but that's okay, he likes being different.

He digs tunnels through the dirt and rock with his hardened nails, and searches out gemstones and geodes. He relies on his sensitive eyes to find them in the constant darkness.

Some he eats, others he takes above ground to give to others.

His favorite to eat is amethyst, he figures it's because that's the mineral in his chest.