Silver is a resource that you can process exactly the same way as gold, and something you may want to collect if you need to obtain some of the things gold allows you to get as well (like Alchemical Base, for example), making it an ore as valuable as gold in Conan Exiles. You can learn more about Silver by taking a look at this guide: https://conanfanatics.com/gameplay/conan-exiles-silver-dust/