Dark Ore is a cargo item from Spirit Tracks. It can be purchased from the Dark Ore Salesman at the Dark Ore Mine for a price of 200 Rupees. The Dark Ore is meant for dark areas, but when it is exposed to sunlight, Dark Ore will begin to melt and disappear, making it necessary to have a swift delivery.
Link can acquire five pieces of Dark Ore and have them delivered to Linebeck III at the Trading Post for a Force Gem. This Force Gem will open up more Spirit Tracks within the Ocean Realm, giving Link access to the Lost at Sea Station. For any repeat efforts of bringing five more pieces to Linebeck III, Link will be rewarded with a treasure, sometimes as rare as an Alchemy Stone.