AfricaEditAdamantium is a metallic compound developed for Weapon X after using an unknown element found in a meteorite somewhere in Nigeria by William Stryker and Team X.
Stryker and the Weapon X team then proceeded to inject the adamantium into the skeleton and bone-claws of Wolverine making him indestructible. When he is later shot in the head with bullets made of the compound, he sustained severe intra-cranial trauma that induced extensive amnesia.
15 years afterwards and beyond, Wolverine's memories began to return to him, and by the time of the events that occured in The Wolverine, he managed to regain many of lost memories.
Sabretooth wanted to be in the experiment that his brother was in. Stryker said he couldn't survive and rejected the deal after Sabretooth did what was asked.
Stryker later gave similar claws to Lady Deathstrike, his controlled bodyguard, extruding from the tips of her fingers. However, in a battle with Wolverine, he defeated her when he impaled her with the Adamantium which engulfed her entire body and perserved her.