Metals Description Guide
So, what is your jewelry actually made of? What is the authenticity of your precious jewelry and blended metals? How should each specifically be treated? How about the durability of your treasured accessories, and what is the historical significance behind the substance of your personal effects? Read on – find out.
Gold is valued by many cultures, world wide, and was the first precious metal to be worked with by man. Pure gold has a rare and lustrous bright yellow color, and the metal’s resistance to corrosion keeps this color bold and strong. It is found in nuggets and was discovered after copper, which makes it the second metal to be worked by early man. Gold’s uses can be dated back to as early as 3000 B.C.
Chemical element symbol: Au
Latin name: Aurum; “shining dawn”
Atomic number: 79
Melting point: 1063 Celsius/1945 Fahrenheit
Atomic weight: 197.2
Decimal Equivalents of Karats
10K = .4167
14K = .5833
18K = .7500
24K = 1.000
Solid gold is too soft for most uses, which is why it is combined with other metals to increase its hardness. Two of the most common additives are (but not limited to) Silver and Copper (as a variety of other metals may be added). The amount of gold in the mixture is referred to by the term “karat”. This word denotes proportion and should not be confused with the carat, which is a unit of weight.
Testing the authenticity of gold requires the application of a chemical called nitric acid to the metal in question. To do this, make a small scratch in an inconspicuous spot on the metal and, while wearing rubber gloves, use a wooden/glass/plastic stick to apply a drop of nitric acid to the spot. Observe the reaction. When done, thoroughly rinse all articles used in running water.
No reaction = it’s gold
Bright Green = its base metal
Green in scratch = gold layer over base metal
Milky in scratch = gold over silver
Gold has been a commodity for trade in the form of nuggets and jewelry for centuries. Actual gold coins intended for trade were made from 1526 on into the 1930’s. Each coin was made of 22 karat gold, containing a percentage of other metals for hardness to retain its shape.
HISTORY AND USES
Historically, gold was valued beyond its worth in currency. It was a common belief in the Middle Ages that something so rare and beautiful could not be anything but good for you. Similarly, treatments – and treats! – that involve gold exist today. Gold flakes or powders are used in some pharmaceuticals and anti-inflammatory medicines to treat arthritis. Gold is also a popular metal in dentistry in its use to fill or cap a tooth. Gold is used in some liquor as “gold water”, sold in Germany, Russia and Poland, and gold flakes and leaves are used to decorate desserts in the culinary trade world-wide.
Still, jewelry is by far the most common use for gold, which has several variations. Rose gold is a popular strain found in Russian and antique-style jewelry. It is 18K gold, combined with 25% copper to create the rose or pinkish color of the metal. Alloying iron, which results in an extremely hard substance, yields blue gold. Its brittle consistency makes it very difficult to work with. Purple gold is a gold-aluminum blend, which is rarely manufactured outside of custom creations. White gold contains 17.3% nickel, 5.5% zinc and 2.2% copper, is silver in appearance, and is illegal to buy or sell in Europe and Japan due to nickel’s toxic qualities. Nickel-free alternatives to white gold include palladium metals (which tend to be pricier than nickel-blended metals) and sterling silver. White gold high in karats has a higher resistance to corrosion than silver and sterling silver.
Gold is found in large quantities in Egypt, and Africa.
Gold-filled is a term that is used to describe a metal that has been bonded with gold. It consists of a gold layer that is bonded to a base metal, usually brass, through heat and pressure. This fusion creates gold-filled metal. 12kt gold is the most common karat weight used in this type of bond, which is half the pure measure of gold. If this metal is melted down it would yield five percent, or 1/20th gold. 10kt gold and 14kt gold are also used in bonding for gold-filled metals.
When properly alloyed, gold-filled metals have the look and luster of gold. They are affordable alternatives to the real thing with all the beauty, prestige and glitz that gold provides.
Silver is most common in the form of jewelry. Popular for its luster and shine, it is a relatively affordable metal, which makes it easily accessible. Practical silver jewelry is popular for men, women and children alike, so it is one metal that will always be in style. It is especially popular in New Mexico, Nevada, Arizona and Mexico where silver mines are prevalent. Silver jewelry can be casual or elegant, and versatile in its ability to compliment any skin tone.
Chemical Element Symbol : Ag
Latin name: Argentum
Atomic number: 47
Hardness: 3.25 mohs
Silver is a soft metal that is ductile and easily tarnishes. Silver is considered a precious metal and has been used in silverware and jewelry for many centuries. Silver became more popular around 1492 when silver mines were discovered in Mexico, Bolivia and Peru. At the time, technology was also improving so that silver could be more easily extracted from ore. Standard silverware is 92.5% silver and 7.5% copper. The copper adds to the hardness factor of the tableware, which makes it more durable and longer lasting.
HISTORY AND USES
Human uses for silver can be traced back as early as the 4th millennium BCE. In folklore, silver is portrayed to have lunar properties and is therefore affiliated with creatures of the night. For example, the silver that gives mirrors its reflective quality is said to be invaluable in warding away vampires by exposing their lack of soul. Similarly, silver bullets are the only known defense against the mystical werewolf.
Silver is applied to food and desserts for decorative purposes and is also used in clothing. One might consider this to be a waste but the silver mineral, in fact, inhibits bacterial and fungal growth and is therefore an invaluable addition to these items’ chemistry. Silver is incorporated into clothing articles in two ways: One is through nanotechnology, and the other is through coating each individual thread with silver to create a metallic shine. In the Middle Ages, Romans and Greeks chose the healing properties of silver for use as a disinfectant, in the dressing of wounds, and to properly store food and purify water.
Silver is also commonly used in photography and dentistry. It is a familiar metal now that is one-fiftieth the price of gold and seventy times more valuable than copper.
Platinum is a dense, white metal with a high resistance to corrosion. When encountered by the invading Spaniards in 1538 it was called platina because of its similar appearance to silver, or plata.
Chemical Element symbol: Pt
Atomic number: 78
Platinum has a number of metals associated with it, including palladium, rhodium, ruthenium, iridium, and osmium. These metals, known as “platinum metals”, have a high melting point and require that separate tools be used when working with each. Also, an oxygen torch is recommended for casting and soldering these materials. Platinum metals must not be crossed with other metals. Cross-contamination by other metals will lead to intercrystaline cracking at the grain boundaries. There is virtually no way to correct this problem.
Platinum is a heavy, ductile, malleable, precious, grey-white transition metal. Platinum can be found in jewelry, laboratory equipment, electrical contacts, dentistry and emission control devices.
In its pure form, platinum has a solid consistency and appears grayish-white in color. It is a metal that is corrosion resistant. Platinum’s durability and tarnish resistant characteristics are well suited for fine jewelry. Platinum also does not oxidize in the air at any temperature. Because of these attributes, platinum is more precious than gold (2x), with a price tag which fluctuates based on its availability.
HISTORY AND USES
Historically, platinum alloys have always been quite common. Pre-Columbian Native Americans discovered platinum, however, the first written record referencing platinum comes from Europe in 1557. Julius Caesar Scaliger, an Italian writer, described it as “a mysterious metal found in Central American mines between Darien (Panama) and Mexico.”
Platinum was traditionally known as a rare metal because of the skill required to work with such a firm, complicated material. This changed, however, in the 20th century when platinum mountings became popular for diamond settings.
Copper is a reddish metal; it has this color because of its band structure. In it’s liquefied state, copper appears to have a greenish hue, and this is a characteristic that is shared with gold. When under the light copper has a bright luminescent glow of a pinkish hue.
Chemical element: Cu
Latin name: cuprum
Atomic number: 29
Melting point: 1083 Celsius/ 1981 Fahrenheit
Copper is a readily used metal. It is found in a variety of products and has been used by many cultures for centuries. Copper was most likely the first metal to be put to used by early man and, today, remains an important and useful element. It can be formed and combined with an array of metals to create a broad range of alloys. As copper is a very ductile metal, it is used to conduct electricity and heat and is used as a building material. Its high thermal and electrical conductivity is second only to silver among pure metals at room temperature.
In metal-smithing copper is often used for experimentation when learning to hone one’s skill. Because it costs so much less than silver or gold, copper offers the perfect material with which to work in a learning curve!
Copper is sold in standard sheets of 3ft x 8ft and in coils 12” and 18” wide. When ordering the metal one must specify the temper, or degree of hardness of the metal: hard, half-hard or annealed (which is copper heated to a soft form).
When copper is hot-rolled it develops a slightly rough texture, which is why most people prefer a cold-rolled material for this reason. Copper alloy #110 is a common choice.
When exposed to moist air, copper forms poisonous acetates, sulfates and chlorides known collectively as verdigris. The name comes from “vert-de-grice”, Old French for “Green of Greece”, a reference to metal sculptures of antiquity. Because of these chemicals, workers should always wash their hands after long hours working with copper. Also, copper silverware and cookware should be plated with a non-corrosive metal such as tin or washed before each use.
HISTORY AND USES
Archaeological finds indicate copper was first discovered by humans in 8000 B.C.E. Two thousand years later, Egyptians began shaping weapons out of the metal. In 5000 BCE copper was discovered and beginning the Bronze Age. In 3800 B.C. there is evidence of controlled bronze alloying and in 2750 BC Egyptians were found to have made copper pipes. During the Roman Empire copper was primarily mined on Cyprus – hence the origin of the name Cuprum, or “metal of Cyprus”. Today, copper is extracted from sizeable reserves in pit mines located throughout the United States and Chile. In the past decade, the price of copper has spiked.
Copper mining in the United States began around the year 800 by the early Spanish settlers and Native Americans. One of the first copper mines is located in Connecticut and was mined by the Europeans. Vermont is home to one of the most well known mines, the Elizabeth (or “The Liz”), which produced copper in large-scale amounts from the 1700s until its close in 1958. U.S. copper production moved westward in the 1800s into Michigan, Arizona and Montana. Today copper is mined in Nevada, Tennessee and Utah. Copper is Utah’s state mineral.
Copper is an essential mineral that is found in high doses in plants and animals. In animals, including humans, copper can be found in the blood stream, and as a co-factor in various enzymes. However, in large amounts copper can be harmful and even fatal to organisms.
Copper jewelry is found in Mexico, New Mexico and around the world. It is an inexpensive metal that is often used in commercial ventures, large experimental projects and for its unique colors. When mixed with chemicals, copper turns a variety of interesting hues; this can create an unusual and interesting design. In jewelry, copper pairs very nicely with brass.
It has a nice yellow color and is used in decoration and application.
Brass is not its own element, but an alloy composed of copper and zinc: a combination that yields a yellow metal that is tougher than either of its components. Brass is widely used because of its malleability, machinability and its resistance to corrosion. In comparison bronze is an alloy of copper and tin. Despite this distinction some brasses are called bronzes.
Working with brass is fairly trouble-free. With a high malleability and relatively low melting point (954 C / 1750 F), it flows fast and is cast with ease. Augmenting or decreasing the portions of copper and zinc blended with brass affect the consistency of the product – making it harder or softer.
HISTORY AND USES
Brass is a substitution alloy. It is used in locks, gears, bearings, ammunition and valves. Brass is often used in musical instruments, such as horns and bells for its acoustic properties.
Humans have likely known brass since prehistoric times, even before zinc itself was discovered. Melting copper together with calamine, a zinc ore, produced it. It was discovered in an ancient Roman settlement in a German village called Breinigerberg, where a calamine ore mine existed.
During the melting process zinc is extracted from the calamine and mixed with the copper. Zinc, on the other hand, has too low of a boiling point to be produced through ancient metalworking techniques. This means that the many references to “brass” in Bible: The King James Version may actually be linked to bronze alloy (which is copper), rather than the strict definition of authentic brass.
Today almost 90% of all brass is recycled. The recycling procedure is done by passing material along a powerful magnet that – due to the magnetic qualities that brass lacks – separates the scrap metal from the brass. From there, the brass scrap is transferred to a foundry: a place where melted is recast into billets – produced either as a coil or cut lengths. Then the billets are sold so the metal may be re-shaped and re-used.
Brass is sometimes integrated in jewelry design. The layering of antique brass chains creates a beautiful, old-fashioned air. Brass is also worked in with copper to give a two-tone jewelry design. Brass has also been used to make large-scale statues and sculptures, having been used by artists such as Auguste Rodin (who is famous for sculpting and re-sculpting his famous bronze sculptures again and again in his quest for perfection) and, controversially, by his girlfriend, Camille Claudel.