Mastering the Elements-
Reaction: After this card enters play, target your Spell and pay Gold equal to its base Gold Cost: This card permanently copies the Spell's keywords, traits, and its base abilities that do not themselves copy abilities. Gold Cost-0
Gold and Steel-
Text Battle/Open: Target one to three attachments with a Gold Cost of 0: Destroy them. Battle: Choose your performing unbowed Personality and target an enemy Personality with an equal or lower Gold Cost: Bow him. You may move him home.
Can i use Gold and Steel to destroy Mastering Elements after it copies another spell in play or is a card's gold cost a trait. Hence if it copied a 4 gold cost spell would Mastering the Elements be a 4 gold cost spell now and ineligible for destruction from Gold and Steel?