Understanding Silver

Silver, the elementIn order to understand silver, we must first know a little chemistry. Don't panic! We only need to know a little, and it's simple stuff:

Some substances are referred to in chemistry as "elements". For example: oxygen is an element. Represented by "O" on the Periodic Table of Elements. 100% pure oxygen is composed of oxygen atoms, and nothing else; just oxygen atoms.

The same is true of hydrogen. Hydrogen is another element. "H" on the table. So pure hydrogen is all hydrogen atoms and nothing else.

Silver - Ag on The Periodic Table of ElementsWater on the other hand, is made from a mixture of hydrogen and oxygen atoms that are joined together. So even pure water is a mixture of hydrogen and oxygen atoms. You have most probably heard water referred to as H2O. This tells us that each oxygen atom has two hydrogen atoms bonded to it.

The same is true of metals:

Copper is an element (Cu). Zinc is an element (Zn). Brass on the other hand is a mixture of copper and zinc. In terms of metals, a mixture is referred to as an "alloy". So you have elemental metals, and we have alloys.

Pure Silver vs Sterling Silver

Silver is an element (Ag). So 100% pure silver would contain nothing but silver atoms. In reality, 100% purity is pretty much impossible to achieve, so anything over 99.9% is regarded as pure. Sometimes you will see pure silver referred to and marked as 999 silver.

Most people are surprise to hear that Sterling Silver, or 925 silver, is actually an alloy with only 92.5% silver. The remaining 7.5% is mostly copper. This is done, not to reduce cost, but because 999 silver is too soft to be of much practical use. The copper is added to make it hard enough to stand up to the rigours of everyday wearing and use.

Hallmarking

Beware of 925 and 999 marks. Strictly speaking they are "marks" and not "hallmarks". Stamp with 925 and 999 on them are readily available. Anybody can buy them and stamp them onto anything they like. It would of course be fraudulent... but you'd have to catch them.

Official hallmarking is entirely different. It can be faked, but you can't just buy a ready to use stamp as you can with 925 and 999.My personal makers mark

So how do things get hallmarked?

To get a piece of silver hallmarked in the UK, you first of all need to register with one the four "Assay Offices", located in Birmingham, Edinburgh, London and Sheffield. As part of this application you request a "maker's mark", which is unique to you at the office with which you are registered (another maker might have the same mark at a different office). When you want something hallmarked, you send it to the assay office who will verify that it is what you say it is, before stamping or laser etching three marks on it:

The four UK assay office marks

  1. Their office mark
  2. Your makers mark
  3. A mark to show what metal it is

From this, you will have gathered that getting something hallmarked, costs extra. Firstly a maker has to be registered, secondly each piece has to be sent to the Assay Office and a fee is paid (on top of what it costs to send it). Of course this cost has to be passed on to the customer... which is one reason that relatively inexpensive items are merely stamped 925.

In the UK, a piece made from Sterling silver that weighs less than 7.78g can be sold as Sterling silver without official hallmarking. Anything weighing more than 7.78g must have an official hallmark if you want to call it Sterling silver.

Silver Colour or Silver Metal?

Of course the word "silver" might not mean the metal element at all as it can also be used to describe the colour of a thing. So a "silver chain" or a pair of "silver earrings" could be made from lots of things. This is why terms like "925 silver" and "999 silver" are useful even though an unscrupulous can abuse it.

The bottom line on whether or not an item is what the seller claims, is to buy from a reputable supplier. That's why I buy all my silver from one of the UK's leading suppliers. Buy on eBay from the far east and who knows what will land on your door mat.

Tarnishing & Non-Tarnishing

Returning briefly to the ol' chemistry class (it's simple stuff again), the fact is that elements like to bond with other elements... and oxygen is a real bugger for it. You've probably heard the term "oxide"? It means that oxygen has bonded with it. So we get copper oxide, silver oxide, iron oxide, and a heap of others. Every metal, and quite a few other things can, and usually do, exist as an oxide. You rarely find metals in nature without something having bonded with it.

Some of these oxides have "special" names. In the case of iron oxide, we call it "rust". In the case of bronze (an alloy) and copper (an element) we call it "patina" and "verdigris". So bronze statues "develops patina"... which sounds much better than saying that the statue of Great Uncle Weathychap The Third has "gone rusty". ;-)

In the case of silver, oxidisation is called "tarnishing"... and silver oxide is black... which is great if it's in the nooks and crannies of an etched piece as it makes the etching really stand out. Not so great when it covers the whole piece. It can be polished off, or removed with a week acid, but repeated cleaning (rubbing off the oxide layer) will, over time, wear away fine details.

A way to avoid tarnishing is to coat the silver with something to prevent oxygen from reaching it. Non-tarnishing, or tarnish resistant silver will generally have been lacquered or coated with a special wax.

Other terms that you will encounter:

Silver Plated

Silver plating is an electro-chemical process in which another metal, usually copper, is coated with a thin layer of silver. In jewellery this is often followed by the application of lacquer or "enamel" to prevent tarnishing. If a plated piece is constantly subject to movement and abrasion i.e. rubbing against things, the copper will eventually begin to show through.

It is a common mistake to think that the piece has become tarnished and rub away even more of the silver in an attempt to return it to shiny silver. Tarnish is black. If you're seeing a copper colour: plating has been worn away. Personally I think this adds character but not everybody agrees.

Sterling Silver Plated

This is a misnomer and in reality there is no such thing.

As already explained: Sterling silver is an alloy i.e. a mic of metals. You can't plate something with 92.5% silver and 7.5% copper. Electroplating just doesn't work like that. The plating process applies a plating of pure silver, not Sterling.

The reason people use this incorrect terms seems to be that:

1. They don't like the term "silver plated" because they feel that the word silver might be perceived as describing the colour of the metal that's been used to plate the object, rather than the metal. Many metals have a silver colour; chrome for example.

2. The term "pure silver plated" sounds like a con... especially if you pause and whisper the word "plated". ;-)

Consequently some suppliers seem to feel that calling a thing "Sterling silver plated" makes the point that it is plated with "real" silver... and then there's the fact that a lot of people don't realise that Sterling silver is actually less pure than pure silver.

Silver Filled

In the same way that "pure silver <pause> plated" gives the wrong impression, so does "silver <no pause> filled". It suggests that something is filled with silver.

"Silver <pause> filled" would be a more accurate way to say it because silver filled is effectively, or can at least be though of, as silver that has been filled with something else, usually brass.

In fact it isn't filled (verb) and filled (noun) wire is made using a mechanical process using pressure and heat.

Being silver filled as opposed to silver plated has two consequences:

The first is that the silver on silver filled wire is hundreds of times thicker than on silver plated wire, and therefore takes much longer to wear off.

Silver filled wire (and chains from that wire) is generally offered in two forms 5% and 10% where the percentage indicates the percentage of it that is actual silver. Clearly 10% has a thicker coating than 5%.

The second consequence of "filling" is that Sterling silver can be used, so Sterling silver filled wire (and chain) has Sterling silver on the outside while the inside is usually brass.

Argentium

Argentum is the old Latin name for silver but Argentium Sterling Silver 935 is the new kid on the block in the world of silversmithing. It contains 93.5% silver along with copper and germanium. This results in a metal that is hard enough to be made into jewellery, but which also has a resistance to tarnishing, and a brighter "white" colour due to the reduction in the "yellow/orange" copper content.

Depletion Gilding

Worth being aware of, this term is borrowed from working with gold (hence the word "gilding"). In terms of silversmithing it is a process by which sterling silver is repeatedly heated and dipped in a mild acid (jeweller's pickle) in order to remove copper from the surface layer.

When sterling silver is heated in a flame it gets marks on it called "fire stain". This happens because of the copper content; you don't get fire stain on pure silver. Dipping the piece into jeweller's pickle removes the copper that's causing the fire stains.

By repeating this process the copper is removed from the outer layer leaving a brighter (less yellow) surface colour. This is particularly important when the piece is to be enamelled with translucent enamels (glass in the case of "real" enamel and usually resin in the case of "cold enamelling"), because otherwise, fire staining of the underlying metal can spoil the effect. Once sealed under the enamel the silver is protected from wear and from oxidisation. If unprotected the pure silver on the surface will tarnish. Repeated polishing plus wear and tear will then the wear it away to reveal the Sterling silver below.

Tibetan Silver

Tibetan silver is similar to pewter - an alloy of copper and tin or nickel, with a small percentage of pure silver. It looks like aged silver, but can be polished. It is significantly cheaper than real silver and many charms and components are available in this metal.

Britannia Silver

In reality you are unlikely to encounter this unless dealing with antiques. I mention it only for the sake of completeness.

Britannia silver is 95.83% silver by weight with the rest usually being copper. The odd number comes about because of the way it was defined when introduced by an Act of Parliament in England in 1697.

Intended as a replacement for the Sterling silver standard, it was the obligatory standard for items of "wrought plate" for 23 years until parliament gave in to complaints from the trade that it was too soft, and sterling silver was again authorised for use by silversmiths in 1720.

Thereafter Britannia silver has been an optional standard and while there are a variety of historical marks, any modern item using it is denoted as 958.

Summary

So, not including silver plated and silver filled, or anything that is merely silver coloured, we have:

999 - pure silver
958 - Britannia silver
935 - Argentium silver
925 - Sterling silver


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