Silver is a resource generated by lands. Unlike the elemental spirits, all lands generate Silver but at varied rates. The two lands that generate that highest amount of silver are Plain Lv.5 Which has a gross income of 12 Silver per 4 hours, this is rivaled only by the Earth Vain Lv.3 which also has a income of 12 Silver/4 hrs.
Silver is primarily used to in the Market, where you can trade Silver for Coin at a rate of [1 Silver : 20 Coin]. It is also a Material for the production of Hairpins and Silver Armor.
It can also be won as a reward in the Lucky Box
Unlike Silver, Gold is not generated by owning lands or Earth Veins. It is obtained through Subjugation, Lucky Box and Daily log-in rewards. It's Primary use is to be traded for Coin at the market at a rate of [1 Gold : 373 Coin] however it can also be used as Material in Producing a Gold Robe and Water bracelet.
Gold can be farmed at Lv. 4-7 Dark Abyss and Lv. 4-5 Land of the Damned.
Like Silver, Gold can be won as a reward in the Lucky Box