Gold Dust
"You got a bottle of Gold Dust! This is the finest quality available! "
Gold Dust is an item that only appears in Majora's Mask and is stored in an Empty Bottle.
Link acquires the valuable Gold Dust after completing the race in first place in the Goron Racetrack. He will later give it to Zubora and Gabora to reforge his sword to the remarkable Razor Sword, which does twice as much damage as Link's original sword, but can only be used 100 times before breaking. It can later be reforged yet again to the Gilded Sword, which is the same as the Razor Sword, but never breaks if Link hands over the Gold Dust again. The Gilded Sword will then be done and acquired on the next day.
Gold Dust can also be sold should Link have no other use for it. He can take it to Zubora and Gabora for a measly 20 Rupees, or he can head over to the Curiosity Shop to sell it for a whopping 200 Rupees.