Europium is a Tier 3 Exotic resource in Starfield that can be hard to farm from different planets, since the best places to find this item may be out of reach of your character's ship. In order to make powerful weapon mods from Europium, you'll need to jump around the galaxy to a number of systems with this material. You may also be able to spend money at the right places to buy this item without any struggle.

Your character can purchase Europium from Jemison Mercantile in New Atlantis or Midtown Minerals in Akila City. Some of the best vendors in Starfield are found at both these locations, selling the material at decent prices if you don't feel like taking the time to harvest Europium yourself. However, you must be at least level 20 to pay for this resource in Akila City, making it a little difficult to collect Europium early on.