Learning Center: Metals

GOLD

Gold is found in nature in several types of deposits and in several physical forms: nuggets, flakes, grains, and even dust.

Most gold used in jewelry is produced by creating alloys of gold with other metals; this affects both the final color of the gold and in some cases it’s durability.

White gold contains gold, nickel, zinc, copper, tin and manganese.
Yellow Gold contains 50% gold, 25% silver, and 25% copper.
Rose gold contains 50% gold, 45% copper and 5% silver.

White gold consists of an alloy of gold with other metals including silver (used for 9KT white gold) and palladium (for 18KT white gold) which provide the whiter color. Historically, Nickel was used to create white gold, however, many people have skin reactions to nickel and so it’s use has dramatically been reduced as an alloy in jewelry.

White gold rings are also often coated with Rhodium to help preserve the underlying metal which is softer and also to enhance the very white appearance as white gold is naturally a light gray color. For this reason, white gold should be re-plated every 1 to 2 years to preserve it’s shiny white color.

Jewelers indicate the amount of gold in an alloy by the Karat system (kt).

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SILVER

Pure silver is 99.9% silver and is usually too soft to create many items. Sterling Silver is typically 92.5% pure silver which is often mixed or alloyed with up to 7.5% other metals such as copper, to increase the strength of the material.

The term Sterling silver seems to have originated around the 13th Century through trade between England and several towns in eastern Germany. These towns used coins to pay for cattle and grain; the coins were known as “coins of the Easterlings.”

It is thought that this term was later shortened to Sterling Silver. Other explanations include a star and starling minting marks made during the production of coins that may have evolved into the term “sterling”. Later King Henry II began producing similar coins which were known as “Tealby Pennies.”

Silver comes from the Anglo Saxon word: Seolfor.

Silver’s atomic symbol Ag comes from the Latin word for silver—Argentium.

Coin silver is lower grade than Sterling Silver and is comprised typically of 90% silver and 10% copper. The coin silver standard was developed by the USA in the early 1800’s.

The custom of a silver wedding anniversary has it’s roots in Germany where silver was used as a gift to celebrate 25 years of marriage.

When buying Sterling Silver always look for the hallmark .925, 92.5%, or 925. Fine silver is usually marked .999.

The trade of silver is regulated by the Federal Trade Commission.

The term “Nickel Silvers” has no silver content.

Many jewelry pieces that have the color of silver are actually base metals which have been coated with Rhodium to make them have a silvery appearance.

To test for silver: place a drop of nitric acid on a discreet place; if the metal is silver plated over brass or a low quality alloy then the drop will turn green. A drop of nitric acid on Sterling silver will turn a creamy color.

Cast silver describes a process where molten silver is poured into a mold to form a shape that can easily be reproduced.

Repousse is silver that has been hammered into a design from the back or inside of the piece.

Chasing is when silver is carved from the outer side of the piece.

Oxidizing is the use of chemicals to darken silver’s lustrous appearance and often provides more depth to the piece.

Tarnish occurs when black silver sulfides form on the surface of silver. Sulphur and sulfides attack the surface of the silver and discolor it. Many types of sulphur and sulfides are in the environment. For example, exposure to eggs or the sulfides created by natural gas will tarnish silver more quickly.

Dental Alloys are usually 60%-70% silver alloyed with tin, copper, zinc, & mercury to create dental fillings.

Vermeil
This is silver that has been electroplated with 100 millionths of an inch of gold. Vermeil is a French word pronounced without sounding the “l” (vermei). Vermeil will often wear off over time with normal wear because it is only a very thin layer of gold over other metals.

Silver Plating
Items that are plated in silver must be marked as: Plated with silver / Silver coated / Silver plated. When purchasing silver plated products, always check that the plating layer has coated the entire piece.

Elemental Silver
Silver can be found in direct silver deposits: silver ore deposits. However, it is most commonly found associated with other metals, in the form of sulfides such as lead (Galena, lead sulfide PbS), zinc (The mineral Sphalerite or zinc sulfide ZnS), or copper (Chalcopyrite CuFeS2). Silver is an excellent conductor of heat and electricity. It is the highest conducting metal and is often used in the manufacture of circuit boards, electrical contacts and in soldering.

Atomic Number: 47
Atomic weight: 107.8682
Melting Point: 1234.93K (1763.2°F or 961.78°C)

Care of Silver

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TITANIUM

Titanium is as strong as steel, but much lighter (45% lighter). It is twice as strong as aluminum. It is nearly as resistant to corrosion as platinum. Titanium is often used in jewelry and is also a component of joint replacement parts, including hip joints. It is produced artificially for use as a gemstone, but it is relatively soft. Star sapphires and rubies exhibit their asterism as a result of the presence of TiO2.

Titanium was first discovered in 1791 but was not manufactured as a pure metal until 1910. It has excellent resistance to sea water and is used for propeller shafts, rigging, and other parts of ships exposed to salt water. The term comes from the Latin word Titans (First Sons of the Earth). Titanium is present in many iron ores and in the minerals sphene and rutile. Titanium is also present in meteorites.

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PEWTER

The beauty of pewter is that it will never tarnish, rust or change (do not place pewter in harsh abrasive chemicals). Pewter allows the artist to show fine detail, with smooth and beautiful finishes.

Sometimes pewter is plated in silver to match other silver pieces.

Several of the charms we use are made of pewter because of it’s wonderful properties.

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PLATINUM

Platinum is one of a group of six platinum-related inert metals (platinum, rhodium, irradium, ruthenium, osmium, and palladium) which occur naturally in the Earth as noble metals. These metals are highly resistant to acids and alkalis and can easily be recycled to their pure form again. Most commonly they are found in South Africa, Russia, and North America and are mined for their use in medicine and general industry. These metals are also used in cancer treatments, air purification, autocatalysts (car exhaust/ emission reduction), and many other aspects of industry to create a cleaner, healthier environment.

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