How Do I Know What I am Really Buying? Part 4

Last time I promised to talk about Plating and Filled Metal

Plating with precious metal has been around for a very long time. Theophilus, in his book “On Divers Arts”, published in 1122, describes how to gild a surface, First you mill together mercury and gold, and then apply it to a metal surface and drive off the mercury to create a gilded surface. He notes “Be very careful that you do not mill or apply gilding when you are hungry, because the fumes of mercury are very dangerous to an empty stomach and give rise to various sicknesses…” And I should mention that the milling process is expected to take three or four hours. Fortunately today there are considerably less toxic plating techniques available, involving electricity and chemical solutions. Until fairly recently almost all precious metal plating solutions contained cyanide, but now non-cyanide plating solutions are available for the shop jeweler. Base metals can be plated with silver or gold, both with the same intention, to make a less expensive metal appear to be a more valuable. Plated pieces should be labeled as plated, and some may be stamped with the purity of precious metal that was used. The layer of precious metal is just a few molecules thick, and there is no standard to indicate how thick the precious metal is. Religious objects were often gilt during Medieval times to make them look as if they were made of solid gold.

Zemanta Related Posts ThumbnailAn exception to the plating rule is Vermeil, which is Sterling silver that is plated with gold. It is an American standard. By law Vermeil has no less than 2.5 microns of karat gold (no less than 10k purity) layered over the Sterling Silver. It is usually stamped Vermeil and may include a purity stamp for the gold. Vermeil is 50 times heavier than standard gold plating.

Beware of “Dutch Gold”. It is not real gold, but rather an alloy of copper and zinc, and is usually sold in leaf form. It is sometimes used to “gild” jewelry and other objects. It can be very beautiful, but it is NOT gold.

Filled Metal is made using a different technique than plating. Filled metal has a physically bonded layer of precious metal that is much thicker than plating. It is attached through a combination of heat and pressure to a base metal core.  When purchasing metal stock from a supplier the metal will be listed according to the purity of the gold or silver. For instance 14/20 or 12/20 for gold means 14K or 12K. The ” /20″ part refers to the ratio of karat gold to core by weight, which is 5%. That means the precious metal is 5% of the overall weight of the metal. Different suppliers use different purities of gold.

English: Diagram of gold filled jewellery

English: Diagram of gold filled jewellery (Photo credit: Wikipedia)

Silver filled has a different annotation system. My supplier lists it as either 1/10 or 1/20, which means a ratio by weight of 5% and 10% respectively; 5% or 10% of the total weight of the metal is silver. I do not use silver filled materials in my shop. I feel that the difference in price is not worth it. But gold-filled materials can allow the customer to have the look of real gold in a product for a fraction of the cost of solid gold.

Next Time: Consequences

How Do I Know What I am Really Buying? Part 3

Last  time we said: Well it looks like silver, but is it?

And now we get into an interesting situation. Two different metals, one of which is a silver alloy, and one of which contains no silver at all – with the same name: Britannia. But they have very different markings.

The first Britannia was, and still is, a standard measure of silver purity in Great Britain. This metal is 95.84% pure silver and 4.16 per cent copper or other metals. The Britannia standard was enacted in Britain in 1697 to try to prevent craftsmen from melting silver coins and reusing them for flatware and hollow ware. It is traditionally stamped 958.

The second form of Britannia contains no silver at all. It is 92% Tin, 6% Antimony, and 2% Copper. It can be stamped “BRITANNIA” or “EPMM”, which stands for “electroplated Britannia Metal”. It is commonly used to make inexpensive hollow ware that is plated with silver. It is also used to make the statues for the Oscars, which are then gold plated.

German Silver contains no silver at all. It is actually a nickel alloy. The alloy that I buy contains 65% copper, 17% zinc, and 18% nickel. I use it mostly for chains, like the one in the picture below. It gives the look of silver without the expense. People with Nickel allergies need to avoid German Silver.

etsy-26-close

And just because it is “silver colored” doesn’t make it inexpensive. Some rather expensive metals are “silver colored”, for example, Platinum.  For a while there Platinum was even more expensive than gold, but now it has come down a bit and is about $250 less than gold, per ounce. Still not an inexpensive purchase.  Platinum is a fairly rare metal and requires temperatures of over 3000 degrees Fahrenheit to cast, so it is rarely used by small independent jewelers.  Platinum jewelry can be stamped “Plat”, “Platinum”,  ” 900 Platinum”, “950 Platinum” or  “586 Plat” depending on exactly the purity level of the metal.

There are obviously many other silver colored metals out there, including tin, pewter, lead, chrome, and aluminum. None of these are currently considered to be precious metals. Back in the early 1900’s aluminum was considered to a really amazing metal, because of its silver appearance but light weight. I have seen some incredible engraved opera glasses and hollowware from this timeframe. Today aluminum is used in jewelry manufacture because it is lightweight and can be polished up nicely. But it is not a precious metal.

So we have now reviewed the major types of precious metals, which we expect to pay more money for because of the increased cost of the basic materials. If you are interested in non-precious metals, and why  a crafts person, like me,  might choose to use specific metals for an assortment of projects, I wrote a blog series about that earlier this year. Choosing Which Metal  to Use, talks about what metals were actually used in period and the decisions that modern jewelers have to make.

Part 1   Part 2   Part 3   Part 4

Next Time: Plating and Filled Metal

How Do I Know What I am Really Buying? Part 2

Last time we talked a bit about gold and its alloys. This time the topic is silver.

Trivia! Silver was often valued more highly in ancient times than gold because it was less common and more difficult to extract. Gold is naturally found in nugget and crystal form. Silver is sometimes found naturally in conjunction with gold. An alloy of gold and silver, called electrum, was used by 700 BC in coinage, and yes, even the Vikings used electrum.

 Anatolian coins – made of electrum.

The vast majority of solid silver items in the US are made from Sterling Silver. The standard for Sterling Silver in the US is .925, which means that it is 92.5% silver and 7.5% other metals. These metals may include copper, germanium, and other trace metals. The “sterling” stamp is commonly used in the US, but it is also acceptable to use a “925” stamp. Outside of the US the stamp usually says “925”. Like gold, Sterling Silver’s color can vary, depending on exactly what sort of metals are in that 7.5%, but silver is generally valued for its “white shiny” appearance. In fact, the ancient Latin word for silver, Argentum, literally means “shiny”. And that leads us to a specialized form of Sterling Silver.

An increasingly popular form of Sterling Silver is Argentium Silver. This is actually a patented formulation that results in a thin layer of germanium on the surface of the sterling. The germanium layer is tough and resists oxidation- this means that the piece will not tarnish easily. While I know people who work with Argentium, it is still fairly uncommon among small producers, because it is a bit fussy. For instance, you can cool regular Sterling by dunking it in water. If you do that with Argentium silver it will shatter like glass. The Argentium that my metal supplier sells is stamped “935”.

Fine silver is 99.9% pure silver. It is usually stamped “999”, or “999F”. Fine Silver is rarely used for jewelry like rings because of its softness. Many enamelists cast their pieces in fine silver, or use fine silver sheet to enamel on, because it is an excellent base for enameling. The lack of copper in this silver means that there is less danger of the enamels changing color by absorbing the copper. Real glass enamel is colored using metal salts.

Coin silver was a standard in the US for silver coins prior to 1964. This silver is 90% silver, or .90. Coin silver from other countries may vary in silver content.

Terms like Bali Silver, Thai Silver, and Indian Silver have no legal meaning in the US metals market. The item must be stamped with a legal stamp to have meaning. I know merchants who sell Balinese silver that is guaranteed to be 925. And it is all stamped  925.

Company hallmarks can often be used on historic silver pieces to determine the actual type of silver that was used. This is an art in and of itself, and many books have been written on this topic, so I will not be discussing it.

Next Time: Well it looks like silver, but is it?