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 is a brittle, silvery white metallic chemical element used primarily in pewter alloys.


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.


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.


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.


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 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.


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.

EU Nickel Compliance

European Nickel Directive – EN 1811 requires a two stage test that simulates – two years wear, and sweat test with nickel migration limited to .5 micrograms/cm2/week for skin contact. A flash layer of nickel is used in the plating process for our Silver, Gold and copper plated finishes. Under normal conditions the nickel is not detectable on the surface of the components and historically these finishes have passed the “wear test”. However, variations in plating result in some plate runs failing the set limits for release in contact with the skin. Therefore, TierraCast is not in full compliance with the EU Nickel Directive for our Silver, Gold and Copper plate finishes. Our Pewter, Black and Brass Ox finishes are Nickel free and are in compliance with the EU Nickel directive.


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 products are a mechanical composition 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. Our Ear wires are 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 (typically bronze or brass) wire core and mechanically clad with a tube of 14k gold that is 1/20th (by weight) of the total weight. The following notes are from our supplier regarding the presence of nickel in Gold-Filled products: "Pink and yellow gold-filled have no nickel added. This is a recent improvement. Traditionally, gold-filled was made with a nickel interleaf. The reason for this was that a layer of nickel would prevent diffusion of the gold into the brass substrate. In recent years improved engineering has allowed the removal of this nickel interleaf. White gold-filled has significant nickel content."


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 was 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. Lead content is now carefully monitored for compliance under the regulations of The Federal Consumer Product Safety Improvement Act (“CPSIA”), CA PROP 65, and the California Metal-Containing Jewelry Law (CMCJL) PROP 65 and CMCJL contain some of the most stringent legal requirements related to lead content in Jewelry Products. Our pewter alloy consistently tests well below the defined ppm thresholds.

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


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 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. Our Niobium wire is sourced from china and made from their local minerals. Nothing to do with Congo where there could be conflict. Our vendor assures us there is no child labor or any illegal behavior. Additionally their factory takes necessary steps to minimize any damage to the environment.

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:



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. Every lot of pewter we purchase is independently tested for both lead and cadmium and certified to meet stringent legal limits.

Plating & Metal Finishes (General Information)

The electroplating of TierraCast cast pewter components is done by standard industry methods. Thin layers of various metals are deposited on the surface by immersing them in an electrolyte solution and passing an electrical current through them. An initial layer of metal may be brass, copper, nickel, or another metal, depending on the metal being plated, the characteristics of the final plate surface, and the practices of the specific plate house. The initial layer of metal seals the surface of the piece, affects the luster and brightness of the finished piece, and provides an attractive or “sticky” foundation for the final plate layer. The final layer of plating, the finish color that you see, is sufficient to withstand subsequent antiquing processes and reasonable wear and tear, but is not so thick as to resist aggressive cleaning or machine polishing. Plating is an art and science and we work closely with our plating partners to achieve consistently beautiful and cost effective jewelry components for your enjoyment.

Plating and the EU Nickel Directive

All of our plate finishes containing nickel are independently tested to assure conformance to the EU Nickel Directive and, other than Rhodium, repeatedly pass the current testing protocol. However, industry regulations continue to evolve. Our commitment is to remain vigilant in providing beautiful and to the extent possible, EU compliant prod.

Precious Metal Plate Finishes:

  • Silver Plate (-11 SB and -12 SA finish designations) uses .999 Fine Silver, the purest form of silver commonly available. Silver plated items receive an under layer of brass or nickel prior to the final silver layer. Antiquing is achieved with the application of a specially formulated metal marking ink which is carefully relieved to reveal the design details. Unlike gold, silver plated surfaces are susceptible to tarnishing but may be brightened by softly rubbing with a jeweler’s polishing cloth, dipping in a mild Simple Green solution (followed by a rub with a soft cotton cloth) or with a quick dip and rinse using Goddard’s silver dip.
  • Gold Plate (-25 GB and -26 GA finish designations) uses a bath of 22k gold that is formulated to an 18k color and a medium luster finish. Our gold plated items have an under layer of copper, then a flash of nickel and a final layer of gold. Antiquing is achieved with the application of a specially formulated metal marking ink which is carefully relieved to reveal the design details. This plating holds up very well in common use. Any cleaning should be done with mild detergents and a soft cloth.

Base Metal Plate Finishes:

  • Black Plate (-13 BLK finish designation) is actually not a plated finish, but rather a chemical oxidization of our unplated pewter castings which are then machine relieved to brighten the surface and bring out the design details, and then finally lacquered to resist tarnish.
  • Copper Plate (-18 CA finish designation) 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 and may be brightened using a soft polishing cloth.
  • Brass Ox Plate (-27 BO finish designation) is brass plate applied thick enough to allow chemical patination and machine relief of the surface. The final finish is then sealed with clear lacquer to reduce the possibility of future tarnish.
  • Antiqued Pewter (-40 PA finish designation) is actually not a plated finish, but rather a chemical oxidization of our unplated pewter castings which are then machine relieved to brighten the surface and bring out the design details, and then finally lacquered to resist tarnish.
  • White Bronze (-70 WB and -71 WBA) sometimes referred to as “Imitation Rhodium” is an “acid tin” bath of tin with organic acid added to facilitate the electromagnetic plating process. This tin plating process is used extensively to protect both ferrous and nonferrous surfaces and is a useful metal for the food processing industry since it is non-toxic, ductile and corrosion resistant.


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.

Some components used in our Jewelry Making Kits do not comply with PROP 65 requirements and are labeled with appropriate warning labels. All of our products that include crystal also carry a Prop 65 Warning. The manufacturers of these products take every caution to limit the presence of lead and cadmium, but with an abundance of caution, we are advised to provide Prop 65 Warnings for these products.


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.


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).

Safety Data Sheet

A Safety Data Sheet (SDS) 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 SDS.

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. All of our decorative Earring Posts are made with hypoallergenic nickel-free titanium posts.


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.

Plate longevity can be affected by many things from the design of the piece to the wearer’s personal chemistry to exposure to elements. A bracelet will be the most tested design. It will get a lot more contact with skin and movement to create more rubbing on the product. This may vary depending on the fit and design of the bracelet; how much of the part is in direct contact with the skin, how much movement the piece has, etc. Earrings will get the lightest wear and rarely have the plate wear off. The chemistry of the wearer and exposure to elements and have the greatest affect. Any lotions or other products that the wearer may use could add to the challenge.

Although our plating is known for durability, plated parts are not a solid metal piece and will not wear like one. Relevant tips to care for your pated parts; Keep it dry – avoid exposure to activities such as swimming, showering or washing dishes; store in dry, sealed containers. Avoid exposure to products – hairspray, perfume, lotions, makeup and cleaning products can affect you jewelry. Put your jewelry on after dressing, grooming or cleaning.


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.