Although they weren't always (see: number 8), Wolverine's claws are now actually fully retractable bone claws. ... In fact, it was in the 1800s (remember, Wolverine is super old) that his powers first manifested after his father was killed in front of him, and his bone claws first burst out of his fists.

Why are Logan's claws bone?

Hint: Magneto is involved

During the final fight in The Wolverine, Logan-San had his adamantium claws sliced clean off by The Silver Samurai, leaving him with organic bone claws that grow back through the stubs of the adamantium coating.

What were Wolverine's claws made of?

Adamantium is a fictional metal alloy appearing in American comic books published by Marvel Comics. It is best known as the substance bonded to the character Wolverine's skeleton and claws.