How do things change when the evidence (knife) is brought into the jury room for examination

When a discussion about the murder weapon, which was identified as the knife purchased by the defendant, a “one-of-a-kind” knife, begins, 8th Juror surprises the others by presenting an identical knife he had purchased in a pawn shop two blocks from where the boy lived a few nights prior, shattering the claim that the knife was so unique and identifiable.