You cannot receive Silver Ore from gathering non-specific rocks (Bloodstone, Sandstone etc) until you are at Skilled 5. This is also the case for most rare ores & gems such as Gold Ore, Rough Emerald, Rough Sapphire, Rough Ruby, Platinum Ore, Rough Topaz etc.

I actually found 2 silver nodes right on top of each other, high on the mountain, East-South-East from Florin.
See screenshot: http://imgur.com/gallery/67ctI

auch ok

Not a single item that give silver from melting?
Edit: you get meldted silver from melting items

Edit:
Just an idea:
https://bdocodex.com/de/item/4251/
you get the melted from all green accessories like talis, baris, elsh etc.Just go to techton and buy the RNG boxes, with luck you get good stuff, if not you can melt the green and still get silver!

https://www.youtube.com/watch?v=vj2UFNU28QA You can find silver ore on map 7/10 also look around the cliffs out side of cave area. There is a spot on hills ledge that has goodies. Put your back to cave entrance look to your right up on ledge, that's the spot. Search Eastern Border Go north east at about 2 O'clock up the hill to rivers end and that's the location. Trent has silver ore around the lake area, just walk east out gate and up to waters edge. Try every rock. It is working for me

https://bdocodex.com/de/npc/10063/

Go to the map link to find all spots