This page offers a guide on where to find all Silica in Gullnámar, in the Dawn of Ragnarök DLC.
There are 8 Silica towers to pillage in Gullnámar and each Silica tower yields 2, so you can obtain a total of 16 Silica. They are exclusively found in raiding locations and can then be used to upgrade your Hugr-Rip. You’ll need to summon your raiding party to obtain the silica and you can either do this via your tool wheel once you’re at the destination, or by sailing into the raiding location’s docking area.
There are three raiding locations in Gullnámar - Stífla Mylna, Hvergelmir Mylna and Sudra Mylna.
Stífla Mylna - x2 Silica
Stífla Mylna is found northeast of Uldar. At this mylna, you’ll find x2 Silica Towers. One is outside in the yard, and the second is behind a door that you can only beat down with another raider. You’ll get a total of 4 Silica from this site.
Hvergelmir Mylna - x3 Silica
Hvergelmir Mylna is found west of Grenhellir Shelter. There are 3 silica towers at this raiding location. One silica is found in building with an open side. The second silica is found in a building with a locked door. You’ll need to enter through a window on the upper floor and use the crank to open up the door so your raiders can help you topple the silica tower. The final one is found up the hill under a pavillion. You’ll get a total of 6 Silica from this site.
Sudra Mylna - x3 Silica
Sudra Mylna is found in the southwest region of Gullnámar. There are 3 silica towers to pillage here. The first can be found a little way up from where you may have docked your ship. The second is found further up in a barn-type building and then the third is found up the stairs from there. You’ll get a total of 6 Silica from this site.