To answer the original question, fine silver is not recommended to use as it is for a ring. It is a way to soft and can’t be hardened enough. That’s the reason why small amounts of copper are added to pure silver. It will work harden the alloy much quicker making it wearable. By using copper one can use the participation process aswell to harden the silver alloy.
Fine silver is a dream to set stones with. However, it will wear in time much faster then sterling silver.
Working with fine silver and opals is a perfect combination. Not as much vor rings but it is perfect for making pendants and necklaces.
Pure silver as it is will tarnish, period.
It’s a reaction of silver and sulfur,.not oxygen.
Sulfur is an abundant element in the air (car exhaust gas, industry air pollution, vulcano’s…), in your sweat and food aswell (onions, eggs, garlic etc). Any layer prevending the contact of silver and sulfur will keep you silver from blackening.
That’s all I’ve to say about that -)