Platinum Coin

100 of them can be obtained from The Desert Dungeon Quest, The Paradox Tower Quest, The Pits of Inferno Quest, The Queen of the Banshees Quest, and the Wrath of the Emperor Quest, 80 from the A Father's Burden Quest, 60 from the Spirithunters Quest, 52 from The Explorer Society Quest, 50 from the Arito's Task Quest and the Nomads Land Quest, 41 from The Scatterbrained Sorcerer Quest, 25 from the Rottin Wood and the Married Men Quest, 22 from the Uneasy Alliance Quest, 20 from the Pilgrimage of Ashes Quest and the To Appease the Mighty Quest, 13 from the Braindeath Quest, 11 from the Goblin Merchant Quest, 10 from the An Interest In Botany Quest, the Frost Dragon Quest, The Ultimate Booze Quest, the To Blind the Enemy Quest, and the Venore Daily Tasks Quest, 6 from the Green Djinn Quest, 5 from the Fishing Box Quest, the In Service of Yalahar Quest, and the Ornamented Shield Quest, and 2 from the Berserk Potion Quest, the Lion Trophy Quest, and the Troll Sabotage Quest. 10 of them are a possible reward in the Liquid Black Quest if all requirements are met. In addition, 20 of them can be obtained for every successful trip in the A Pirate's Death to Me world task. A maximum of 60 can be obtained from Piggy Banks. 5 of them can be obtained from Gnomish Supply Packages and 1 from Shiny Stones.
See also: Gnomish Supply Package/Statistics and Shiny Stone/Refining Statistics