Silver:
Silver is tough but also soft, a gentle reflection of our lunar satellite.
Marked sterling is denoted by .925 (a small mark found on fine jewelry) and this reflects its status as an alloy. Fine silver is too malleable to be reliable in everday use, so copper, zinc, brass, etc. are added to increase durability and wear characteristics. Therefore, sterling silver is 92.5% silver and 7.5% alloy metals. This is a reason that people with metal sensitivities can wear fine silver (.999) but will have a reaction to sterling silver.
Argentium silver is found in my work; which is a slightly higher grade silver alloy. It wears as well as sterling, but remains brighter longer.
Gold-fill:
You know the saying: "A champagne lifestyle, on a lemonade budget".
I love a splash of gold in some of my pieces, but here in Montana, a massive price hike for looks isn't something that all of us can afford. So, hallelujah for gold-fill. 14/20 gold-fill is essentially a jeweler's brass encased by a thin layer of gold (14 karat in my case)
Simply put, this means there is a substantial enough amount of gold to offer good wear characteristics for at least a decade - even up to thirty years - of normal use.
