Alloy
A mixture of two or more elemental metals to form a new type of metal. Alloys are formulated to produce a metal with improved characteristics over the separate components. Pewter, Bronze and Sterling Silver are all alloys that present improvements over their tin, copper and silver core components.
Antimony
Antimony is a brittle, silvery white metallic chemical element used primarily in pewter alloys.
Antiquing
Antiquing is the process of artificially inducing (or mimicking) the natural process of the tarnishing of metals. Depending on the plate type, parts are either darkened with chemical solutions or with specially formulated metal marking inks. Both approaches are carefully monitored to achieve a consistent appearance that creates polished highlights and dark contrasting recessed areas.
Anodizing
An electrochemical process that artificially creates an oxide layer on the surface of a selected metal object by passing direct current through the item while immersed in an electrolyte. On common aluminum objects, anodizing creates the thin layer that can be dyed to brilliant colors. On niobium and titanium the layer itself refracts natural light to create a range of colors without the use of dyes. The color is a factor of the specific DC voltage used on that object.
Avoirdupois [av-er-duh-poiz]
Avoirdupois a system of weights based on a pound of 16 ounces of 28.35 grams per ounce. It is the common weight system used in the United States for everything from coffee to non-precious metals.
Bismuth
An elemental metal often mined as a byproduct of the production of lead, tin, copper and gold. Its most common use in jewelry is as a component in pewter alloys where its unique property of expanding when cooled contributes to replicating detail in castings.
Carat
The smallest commonly used division of the troy weight system. One carat is equal to 3.086 grains. There are 480 grains in a troy ounce. The word carat is believed to have come from the use of carob seeds (in Arabic the name of the seed sounds like carat) in weighing coins and eventually gemstones and pearls.
Copper
Copper is believed to have been the first metal used by man, as it is found in a "native" state that does not need refining from ore before it can be used. Today it is used extensively in all aspects of manufacture of nonferrous (metal with no iron content) products. In its pure state, it is a pinkish red color, easily worked, but subject to tarnish by simple exposure to air. Copper is usually the first layer in electroplating plating and then other metals are plated over it.
Copyright
The Federal Government offers protection from illegal copying of artistic creations, including original jewelry designs. The enforcement of Copyright Law protects the creative output of a company, and ensures fair competition among consumers as to the origin and quality of the product. TierraCast is proud of both its design innovation and product quality and will aggressively defend its rights under Copyright Law.
Gold
Gold is a precious metal whose purity is measured in karats. Pure gold (24k) is very soft. Gold is usually alloyed (mixed with other metals, usually silver and copper) to make it harder and less expensive. Solid 14k is 14/24ths (58.5%) pure gold; the remaining 10 parts are made up of other metals such as copper, silver and zinc for strength, color and other properties.
Gold-Filled
Gold-filled products are a mechanical compositions of thin karat gold layers and base metal cores. The use of heat and pressure bonds the gold karat layer to the base. Gold-filled wire products are manufactured to federal standards, marked and sold accordingly. Ear wires can be made with 14/20 gold-filled wire, which is an abbreviation for their gold content by weight. 14/20 gold-filled wire is composed of a base metal (bronze) wire core and mechanically clad with a tube of 14k gold that is 1/20th (by weight) of the total weight.
Karat
A measurement of the purity (or fineness) of gold equal to 1/24 of the pure state of the metal. Hence 24k gold is 24/24ths pure. This measurement of purity is also spelled carat (though always abbreviated with a k or kt) and should be confused with the system of weight of gemstones.
24k = .999% fine
18k = .75% fine
14k = 58.5% fine
10k = 41.7% fine
Unlike gold, platinum is not alloyed in wide range of purities. The word karat has been adopted in the name of a platinum alloy trademarked as 14k Platinum® or Karat Platinum™, composed of 58.5% platinum and the balance primarily in cobalt and copper.
Lead
Lead is commonly used in lower quality, tin based casting alloys because its addition makes the metal easy to cast, enables well finished surfaces and is much less expensive than tin. However, lead is a known toxin that accumulates in the body causing numerous physical ailments. In recent decades, focus on this problem has resulted in the elimination of lead in gasoline and paint. Recent legislation, worldwide, has focused on the health problem from the high lead content in metal alloys used in items that come in contact with people, particularly children. This has led to the recall of millions of metal jewelry items, many of which were manufactured overseas.
Material Safety Data Sheet
A Material Safety Data Sheet (MSDS) is designed to provide both workers & emergency personnel with the proper procedures for handling or working with a particular substance. TierraCast pewter products do not require a MSDS.
Measurements Conversion Table
| B & S Gauge # | Inches | Millimeters |
| 12 | .081" | 2.057 |
| 14 | .064" | 1.626 |
| 16 | .051" | 1.295 |
| 18 | .040" | 1.016 |
| 20 | .032" | .812* |
| 22 | .025" | .635 |
| 24 | .020" | .508 |
| 26 | .020" | .508 |
* The diameter of the wire in a common paper clip is approx .032" (B & S #20)
Measuring Metal Content
The most common way to refer to the content of various metals that comprise an alloy is by simple percentage. When discussing levels of metal below 1% however, it is more common to transform these percentage numbers into ppm (parts per million). This ppm approach is used by regulatory agencies and laboratories to express standards and report test results.
| Percent | Parts Per Million (ppm) |
95 % |
950,000 ppm |
| 50% | 500,000 ppm |
| 5 % | 50,000 ppm |
| 1 % | 10,000 ppm |
| .06 % | 600 ppm |
| .03% | 300 ppm |
| .01% | 100 ppm |
| .002% | 20 ppm |
Nickel>
A hard silvery-white metal used primarily in alloys of stainless steel, coins and other utility objects. While nickel is an abundant element, as much as 30% of the world’s production comes from an area near Sudbury, Ontario Canada. The standard American five cent coin (also called a nickel) is composed of 75% Copper and 25% Nickel.
It is estimated that 10 - 20% of the population is allergic to nickel, which can cause skin rashes from prolonged contact. The European Community has strict regulations regarding exposure to nickel and regulations limit the amount of accessible nickel allowed in jewelry and other personal items.
Nickel Silver
Also called German silver, alpaca or new silver, This alloy was originally developed by the Chinese who called it paktong. Its strength and silvery white appearance made it attractive for the same decorative and utilitarian purposes for which it is known today. It contains no silver and takes its name from its sterling silver-like color and luster. Various alloys contain high percentages of copper, in addition to nickel in ranges of 10% and higher. It is used worldwide for coinage, eating utensils, musical instruments and other decorative purposes.
Niobium
Niobium is an elemental metal which is strong yet flexible. Niobium is chemically non-reactive, therefore very hypoallergenic. It can be transformed into brilliant colors through the anodizing process. The colors are created by refracted light, do not use paint or dye and do not negate the metal's hypoallergenic qualities.
Periodic Table
A chart or table that graphically displays the earth’s chemical elements in an organized format. Each of the elements is assigned a symbol of one to three digits in length. These symbols are often used in listing the components of metal alloys and in reporting metallurgical test results. The symbols for the most common metals used in jewelry are listed below:
| Ag | Silver |
| Al | Alumninum |
| Au | Gold |
| Bi | Bismuth |
| Cd | Cadmium |
| Cu | Copper |
| Nb | Niobium |
| Ni | Nickel |
| Pb | Lead |
| Pt | Platinum |
| Rh | Rhodium |
| Sb | Antimony |
| Sn | Tin |
| Ti | Titanium |
| Zn | Zinc |
Pewter
Pewter is a metal alloy, traditionally between 85 and 99 percent tin, with the remainder consisting of copper and antimony acting as hardeners. Lower grades of pewter may contain as much as 60% lead, giving them a bluish tint.
The Federal Trade Commission and the American Pewter Guild define pewter as a "metal alloy product of which the chemical composition shall be not less than 90% Grade A Tin, with the remainder composed of metals appropriate for use in pewter."
TierraCast uses an alloy called Britannia, composed of 92% tin, 7.5 % antimony and .5% copper. Tin is refined from ore that contains other metals, including lead. A chemical process is used to remove the lead, but trace amounts still remain. Although all pewter contains trace amounts of lead, the term "lead free pewter" is used to describe pewter that meets the stringent FDA standard of less than .05% (or 500 parts per million) lead content in pewter in contact with food.
Plating
The electroplating of Tierracast cast pewter components is done by standard industry methods. First, thin layers of various metals are deposited on the surface by immersing them in an electrolyte solution and passing an electrical current through them. While each plated part receives various layers, the final surface offered by TierraCast is one of four common types.
Gold Plate of 22k quality is used on TierraCast parts. We use this 22k formulated to an 18k color and a medium luster finish on all of our cast parts. All gold plated thicknesses are above 10 millionths of an inch and thus qualify under the Federal Trade Commission terms of "Gold Electroplate." The plate thickness is sufficient to withstand reasonable wear and tear, but is not so thick as to resist aggressive cleaning or machine polishing. Any cleaning should be done with mild detergents and a soft cloth.
Silver Plate is done using .999 Fine Silver as the final plated surface, and has a thickness of at least 20 millionths of an inch. Unlike gold, this plated metal surface is susceptible to tarnishing but may be brightened by several methods covered in the Q & A section of this website.
Rhodium Plate is often used as a "silver colored" alternative to real silver plate. While more gray in color than silver, Rhodium is highly scratch resistant and does not tarnish.
Copper Plate is applied in thickness sufficient to allow for chemical antiquing and machine relief to give the plated parts a natural antique look. Like silver plate, it is susceptible to natural tarnishing as well and may be brightened using a soft polishing cloth.
Platinum
A grey white metal with strong corrosion and wear resistance. Mined as a by-product of copper and nickel it is more rare than gold its most common use is as a chemical catalyst, including use in catalytic converters for automobiles.
Its malleability, wear resistance and bright luster have ensured its place as the pre-eminent precious metal in jewelry applications, especially with the additions of gemstones such as diamonds.
Proposition 65
TierraCast cast pewter products do not require labeling with Prop 65 notices. California's Proposition 65 regulations set Safe Harbor levels for exposure to a long list of chemicals, and adopted a range between .5 and 15 micrograms a day as the limit for lead. The .5 microgram limit is that most often cited, as it serves as the Safe Harbor level to prevent reproductive toxicity. Items containing levels above those values must be marked with a Prop 65 warning notice, notifying potential buyers that the items contain lead in quantities that pose a potential health risk.
Rhodium
Rhodium is one of the six metals in the group that contains Platinum and other noble or precious metals. It is rare, chemically stable, and highly resistant to oxidation and corrosion. It is commonly plated on white gold diamond setting to enhance the stones appearance and on sterling silver neck chains to protect them from tarnishing. Rhodium is ideally suited for the jewelry industry. It is a sought after, long lasting, and non-tarnishing finish. Its brilliant gray-white color is compatible with sterling silver and silver plated products.
Silver
An elemental metal often associated in natural ore deposits with copper, gold, lead and zinc. In its "pure" form it is a relatively soft, white colored metal generally unsuitable for jewelry or other functional objects. Silver is usually alloyed with other metals. The resultant alloys are usually marked with their degree of purity or "fineness" using a scale up to 1000. Varying degrees of fineness have been used as standards for coinage, tableware and jewelry ranging from .980 (common in Mexico in the 1930s) to the .800 range for various coins minted in silver alloys around the world.
Fine Silver (marked .999) is the most pure form of silver commonly available, and is used in photographic film, some electrical applications and as a decorative plating. The appearance is less gray in color than nickel or rhodium, though it will tarnish with exposure to air.
Sterling Silver (marked .925) is an alloy of 92.5% silver and 7.5% copper. The sterling alloy produces a metal that maintains the lustrous white color of silver while increasing the strength and durability. TierraCast wire products (ear wires and sterling coils) are made from sterling wire supplied by reputable domestic suppliers.
The strongest theory as to the derivation of the name sterling is based on the standard silver alloy from an area known as “The Easterlings” in Germany. This simple alloy of silver and copper was adopted by Henry II of England as the standard for English currency and become known as Sterling.
Argentium® Sterling Silver, (marked .925) a patented sterling alloy that includes germanium to produce a metal with both increased strength and resistance to tarnish. The name Argentium ® is derived from the Latin word for silver, Argentum (hence the use of Ag as silver’s symbol in the Periodic Table)
Stainless Steel
"Stainless" steel is an alloy developed in the early 1900's that contains over 10% chromium. Nickel and other metals with corrosion resistance properties are also added to the steel to create a range of alloys that are stain resistant and used in a wide range of products, including cookware, aircraft parts and jewelry components. This range of alloys has also been referred to a "Surgical Steel" and previously used as a hypoallergenic replacement for copper based components, particularly body piercings, like ear wires or posts in earrings. Concern over allergic reactions to the nickel content in some stainless steels has encouraged jewelry manufactures to substitute completely hypoallergenic titanium ear posts.
Tarnish
When metals tarnish (discolor with grey, brown or black spots or streaks) a thin layer of the metal is actually combining with oxygen and other chemicals in the air or water to form oxides of the metal surface. The most common tarnishing is caused by simple contact with air. Sulfur and other natural elements are the cause. An extreme example can be seen if silver or copper jewelry is worn into a natural sulfur hot spring. Tarnish on TierraCast's plated silver parts is a result of having been plated with .999 fine silver, which forms a yellow-tan oxide. In comparison, most sterling silver forms a grey-blue oxide more commonly recognized. Protective coatings are often applied to metal parts in an attempt to inhibit this process. They can be more or less effective depending on how successfully they isolate the metal from contact with other substances, including contact with the skin. These coatings usually have a short life and are easily scratched or worn off.
Titanium
A strong light weight metal used in surgical implants and industrial uses where corrosion resistance is required. Titanium alloys are used in everything from jewelry items where its hypoallergenic properties virtually eliminate adverse reactions, to airplane parts where strength and heat resistance are crucial. Like niobium, the surface of titanium can be transformed through anodizing, which can create a range of bright colors without dyes or paints.
Troy Ounce
The customary unit of weight for precious metals and, through its division into carats, the foundation of the weight system for gemstones. 151.5 carats equal one troy ounce. One troy ounce (ozt) is equal to 31.1 grams, or roughly 10% more than an avoirdupois ounce.
