Couple things that no one has mentioned. Silver veins are only found above the obsidian line on the mountains so don't waste your time looking for it in the foothills. Mine the obsidian, it makes better arrows than what you're using if you haven't been into a different biome yet. Golems spawn near abandoned houses OR silver deposits. If you didn't find a house where a golem spawned use the wish bone to find the silver vein. Look in the chests in the buildings that's the only place you will find onion seeds.

If your wish bone keeps beeping once you've mined out a silver deposit change position again and keep digging. Silver veins often come in twos or threes.
https://steamcommunity.com/sharedfiles/filedetails/?id=2856429325

Sometimes the wish bone will only find a buried skeleton but that skeleton usually has a silver necklace.