I love and can wear silver. I have a box link chain I wear daily.
It does tarnish, but typically it makes the piece look like an antique. You can remove the patina if you don't like it.
You want to be sure to get .925 sterling at the least. If you're set on a diamond you'll probably need to specify that when at the jeweller. I want to say most of them would be set with cubic zirconia for reasons related to cost, as silver is cheaper than gold and the like. My ring is set with a small one. I personally can't tell the difference but I'm blind lol. They're worth next to nothing though and you'd probably feel cheap giving her one.
Speaking of engagement rings though, fun fact. Used to be you gave her a pearl ring for a while. They fell out of favor when marketing for diamonds started(which aren't rare, just highly monopolized by DeBeers) and that silly month/two month/whatever BS budget for a ring happened. I'd be insulted by a solitaire myself. I dislike diamonds for cost reasons.
But I'm rambling.
TL;DR: if getting silver, which is an excellent choice, if you want a diamond/or several) you'll need to specify that. It'll cost more.
As an aside, my titanium band cost about 70 bucks. Compared to my gold with diamonds band.
I'll post a pic shortly for giggles.
Edit.
https://imgur.com/a/cz6bR4HThe stone is set in a little swirly that kinda looks like the hurricane symbol on weather maps. One side is polished, the other a matte finish.
I think it's cute.