In Ultima Thule, you can get Softsilver Ore from an Elusive Node around (X: 16.8, Y: 29.2), with Reah Tahra being the nearest teleport. As soon as it appears, it will disappear until the clock restarts. Wait for the Node to spawn (between 4am and 6am Eorzea Time).
It is likely that you haven’t received and used the Tome of Geological Folklore – The Sea of Stars item yet, which allows you to see special Nodes in the areas if you do not see them despite equipping the correct Job. Splendors Vendor in Radz-at-Han (X: 11.3, Y: 9.1) sells 1600 White Gatherers’ Scrips (total price for the Folklore Totems).