Godric Gryffindor's goblin-made sword is silver and inlaid with rubies. It belonged to the founder of Hogwarts: Godric Gryffindor.
This sword is clean, but it retains what "makes it stronger" like the Basilisk poison. The goblins claim that he stole it from Ragnuk the First simply because it was built by them. Godric did not steal it. Only true Gryffindors can carry the sword, such as Harry Potter and Neville Longbottom.
Albus Dumbledore bequeaths the sword to Harry, but the Ministry won't allow it. They use it to destroy horcruxes, after it became impregnated with basilisk venom. Harry promises Griphook the sword in exchange for help getting into Gringotts but Neville later retrieves it through the Sorting Hat by killing Nagini with it.