Solsken Design Sterling beads on sterling hoops
In this first post on jewellery components, you will learn about chemical properties of silver, how it is used in jewellery, and the price of silver.
The symbol of the chemical element silver is Ag for Argentum, which refers to grey or shining, and its atomic number is 47. Silver is a metal and you find it among the transitional elements in the periodic system. Like all metals, once it reacts to become an ion, its charge changes from neutral to positive. Metals are charged differently though, with either one, two or three lost electrons from the outermost shell. Silver has only one electron in that shell and, hence, its oxidation number is +1 when reacting with other elements to form compounds.
Silver can not only occur in its pure state, but it exists in several alloys. The alloy is a mixture where the primary constituent is a metal. The same way as in liquids, the primary constituent is called a solvent, whereas the secondary constituent is a solute. The primary metal is also called base or matrix. There can be more than two metals in an alloy and the number is denoted binary, ternary, quaternary, and so on, not including any impurities. If a base metal is abundant enough, the whole alloy takes its name.
Another use of the expression base metal is when describing metals in the context of reactivity in moist air. Noble metals are resistant to oxidation and corrosion, whereas base metals are not. Precious metals on the other hand are described as valuable out of a financial aspect and rare on Earth. Reactivity is compared in an electropotential series (galvanic series) and tarnishing of silver has to do with this (more later in an article on how to care for your jewellery).
So, what about silver alloys, why should you care about them? Jewellery is made from silver alloys, not pure silver, which is why I’m pestering you with this much chemistry. You need to be aware as a consumer, so you know what you are spending your hard-earned money on. In jewellery, silver is considered a precious metal, meaning when I buy components, I need to be able to trust the supplier. And I’m doing my best to earn your trust in turn. I’m not taking this lightly, because there’s the occasional fraudulent product in circulation, pretending to be more pure silver than what it truly is.
Confusing is also how the word silver is used. It can describe a colour, which is something I also do when appropriate, because customers think in those terms and search for products using that word. Silver-coloured when describing components, however, usually means that there is silver as a coat on top of another metal or alloy such as brass or it is an entirely different metal that looks like silver only. I avoid this altogether and state instead the exact components through silver-plated or whatever is appropriate. Honesty and transparency is my aim and therefore all my item descriptions will state even smaller component constitutions such as those of head pins and bead caps.
So far, I haven’t talked about “silver” at all, the silver alloys, but here we go! Sterling silver and Britannia silver, the latter of which I have yet to stumble upon in a supplier’s store, are pure enough to be called fine silver. In the US, the percentage of silver in an alloy has to be at least 90% for it to be called fine silver. Sterling silver (925S or .925) contains 92.5% silver and 7.5% copper, whereas Britannia silver contains 95.8% silver. When some of the copper in sterling silver is replaced by germanium, a metalloid (element between metals and non-metals), you get Argentium sterling silver, which is a patented and trademarked modern alloy. Argentium silver has improved chemical properties and is very tarnish resistant.
Silver can be plated in various ways. To give sterling silver a shiny surface, it can be coated with .999 fine silver (99.9%) or for increased tarnish resistance rhodium, another transitional metal that is extremely rare and also a noble metal. Gold-filled silver has a much thicker gold coat compared to gold-plated silver, but even this will wear off eventually. Usually, gold is bonded to base metals, but occasionally silver is treated this way too. This will be covered in greater detail in the article on gold.
The price of silver is currently rising. There was a low lasting for about a decade starting at the beginning of the 1990’s, but from that point on the price has been climbing steadily. The price of fine silver is measured in troy ounce (oz t), a unit of imperial measure. One troy ounce is defined as 31.1034768 g and I say use the historic unit, although I normally prefer the SI units… In 2001, 1 oz t cost 4.37 USD and today one pays 34.15 USD for it. If you see my pricing adjusted, this could be a reason.
If you have questions on this, please post in the comments and I’ll do my best to answer them! I’m passionate about silver, as it is a gorgeous metal with such a rich look.
This was first published in November 2012.