To get Silver in Tribes of Midgard, you will need to mine Silver deposits located in the Land of Pools region of the game.
You will also need to get a pickaxe before you are able to mine Silver deposits in Tribes of Midgard. We also highly recommend making at least a stone pickaxe before you mine Silver, as you will get more ore from doing so.
This ore can then be used to upgrade your stone tools into Silver ones and Crystal tools, and other items as well. For example, most uncommon to rare weapons will require Silver as a crafting material, so it's always good to get a lot of Silver for that alone.
That said, you might also want to craft some better armor before heading into the Land of Pools, looking for Silver ore. The reason why is that some strong monsters can roam the region at times, like the Linnorm.
However, you should be safe for the most part as long as you have uncommon gear all around, including armor and weapons. So if you don't know how to get better gear, it's easy, you just need souls, and you need to upgrade both the armorsmith and blacksmith.
Check out some more Tribes of Midgard guides at Pro Game Guides!