Your unlucky, or not far enough form middle.

Big mountains usually hold silver vein's, I'm talking about the really large mountains of the likes you'd find a moder spawn on.
A lot of the time silver is underground that's why the wishbone is needed, a good weapon that helped me out was using a AoE weapon like stagbreaker and hit the ground, if "too hard" pops up multiple times from underground it's most likely silver vein

yes wishbone was used and got nothing not a single ping

As @Starwing6 said, you have definitely equipped the wishbone, have you? I remember exploring a mountain and only realising after 20 minutes that I still had my heavy-lifting belt still equipped...

I just found a map on a steam discussion, it is O00xXXx00O (big letter O, zero, zero small x, big x, big x, small x, zero, zero, big letter O). The first island is huge and has meadow, black forest, swamps, and mountains on the first island. If you go to the south easternmost point of the island, there is a mountain there with more silver than I've ever seen on one peak. Also Moder is on that mountain on the first island.

Mountains need to be tall enough. Obsidian starts to show up about mid altitude.
If you find stone golems that is a pretty good indication you have silver around. Out of 12 seeds I have only found one mountain with stone golems that did not have silver.

I've got pretty good about finding it. Don't even need the wishbone.

ok now its 2 usless mountains no silver

We found some (2 veins) silver on a tiny slice of mountain on our first island, which was a big surprise for me because I heard those tiny ones usually don't have any. Both were guarded by a Stone Golem.

Make sure you have your wishbone equipped and watch for the coloured rays around your character as you explore if you have music on--otherwise you'll hear the pings easily.

If none of that applies to your situation, I'm surprised to hear that a larger mountain biome would lack silver veins. Extremely bad luck, perhaps? Do you know of other mountains you can try?

It's always the mountains with a perfect cliff above a river that have no veins.

Originally posted by Mharr:

It's always the mountains with a perfect cliff above a river that have no veins.

Thanks for the tip! We've found a large, very tall mountain that we haven't explored much, but it has a sheer cliff like that and a stream below. I think the mountain is large enough to have silver elsewhere, but I'll keep your input in mind as we explore there.

Sample size of one here mind, so your mileage may vary, but yeah. So far we've always struck out on giant ranges with easy access to the coast, and found all our silver on tiny single peaks surrounded by miles of swamp and plains. Either the river generation prevents ore spawning somehow or the game just hates me personally. :D