Precious Metal Glossary
Alloy:
An alloy is a mixture of two or more metals usually mixed to enhance the strength and/or appearance of a particular metal. Copper, silver, nickel, zinc etc are frequently used as alloy metals and usually are mixed with all precious metals for some specific purpose.
Annealing:
It is a process of providing multi-phased heat and stress treatment that alters the microstructure of a metal adding strength, pliability and hardness.
Anodizing:
Anodizing is a process used to dye and/or modify the surface of a metal using electrolysis. The dye enters the pores in the etched oxide surface of the metal. Usually metals like aluminum, magnesium, titanium and tantalum are often anodized.
Au:
The chemical symbol for gold. Au is derived from Latin word ‘aurum’ for gold.
Base Metal:
Base metal is a term used to refer any non-precious metal. Generally it is used as a base for gold-filled or gold plated coverings.
Brushed Finish:
A brushed finish, also known as matte finish, is a texture applied to metal surface, which gives a dull and non-reflective finish. In this finish, a firm wire brush is used to give scratches or tiny grooves on the surface of the metal piece.
Buffing:
Buffing is the process refers to the use of grease compound in combination with wheels to produce very smooth polished surface. It is the final step in professional finishing process.
Burnishing:
Burnishing is a finishing with shiny surface usually resulting from using a dull or loaded grinding wheel or coated abrasive.
Burr:
Burr refers to a sharp edge of metal which remains on the surface of metal after cutting and reforming.
Casting:
Casting is a widely used jewelry manufacturing process, in which a molten material such as metal, plastic or any other material is poured or forced into a hollow mold and allowed to solidify within the mold and then ejected or broken out to get a fabricated jewelry part.
Cleaning:
Cleaning of metal casting refers to all activities that are performed to remove sand, scale and / or excess metal from the casting.
Die Struck:
Die struck is a process of reproducing an object by pressing or striking a piece of metal between a pair of dies. This pair consists male and female patterns to form highly detailed impressions on that metal piece.
Dwt:
Dwt is used as a symbol for ‘pennyweight’ that is 1/20th of a troy ounce or approx 1.555 grams.
Electroplated:
This term is generally used for jewelry items that have been coated with gold through the process of electroplating.
Electroplating:
Electroplating is the process where inexpensive metals are frequently electroplated or coated with a thin layer of more expensive metals like gold (gold plating), silver (silver plating), rhodium (rhodium plating), copper (electro coppering) etc. In this process, an electric current is flown to coat an electrically conductive metal object with a relatively thin layer of precious metal.
Enamel:
Enamel is a colored, opaque glassy material fused onto metal, pottery or glass to achieve a vitreous or glass-like, decorative surface.
Engraving:
Engraving is a method of surface decoration in which a design is etched or engraved with a sharp tool.
Etched:
It is very faintly carved decoration scratched onto the surface of a metal piece.
Findings:
Jewelry findings are basically components, materials and elements such as clasps, pins, hooks, tabs etc that can be used in making or assembling a piece of jewelry.
Finish:
The way the surface of a piece is cleaned or polished or textured. Finish refers quality of polish and symmetry on a gemstone as well as polish or texture applied to the metal on an item of jewelry. Common metal finishes include florentine, high polish and matte or brushed.
Florentine Finish:
A Florentine finish is a crosshatched decorative technique engraved into the surface of a precious metal. It is usually applied by a hand tool and consists a series of parallel lines engraved in two directions perpendicular to each other. This finish reduces the reflectivity of metal and the lines are often coarser and more deeply incised than the brushed or matte finish methods.
Forging:
Heating a metal to a temperature where the metal becomes malleable (red hot) or deforming its shape by compression or exertion of force (by hammering or cold forging).
Gallery:
Gallery is metal strips used to make settings for gemstones or used as a decorative design element in a piece of jewelry.
Gold:
Gold is an extraordinary and rare precious metal, with an unmatched combination of chemical and physical properties. Gold is the most non-reactive of all metals and it does not oxidize under ordinary conditions. No other metal is as malleable as gold. Pure gold is very soft and pliable, and alloys of different other metals are combined with pure gold to enhance its durability and strength, as well as creating a blush in the gold’s appearance with different color tones. 24 karat is 100 % pure gold, and it is more expensive and less durable than gold that is alloyed with other metals.
Gold - 10 Karat:
Gold which combines 10 parts of pure gold and 14 parts of other metal alloys and appears in natural yellow tone. By combining with copper and silver, yellow gold retains a rich yellow color while increasing its strength.
Gold - 14 Karat (white):
Gold which combines 14 parts of pure gold and 10 parts of other metal alloys and appears in white tone. As mentioned above, normally white gold is created by combining pure gold with a copper, zinc and nickel (or palladium) alloy.
Gold - 14 Karat:
Gold which combines 14 parts of pure gold and 10 parts of other metal alloys and appears in natural yellow tone. As mentioned above, by combining with copper and silver, yellow gold retains a rich yellow color while increasing its strength.
Gold - 18 Karat:
Gold which combines 18 parts of pure gold and only 6 parts of other metal alloys and appears in natural yellow tone. As mentioned above, by combining with copper and silver, yellow gold retains a rich yellow color while increasing its strength.
Gold Filled:
Gold filled refers to a layer of at least 10-karat gold that has been permanently bonded by heat and pressure to the surface of the base metal, then rolled or drawn to a prescribed thickness. The karat gold must be at least 1/20 of the total weight. It is also known as gold overlay.
Gold Tone:
In its pure form, gold has a metallic luster with deep yellow in color, but when it is mixed or alloyed with other metals, such as silver, copper, zinc, nickel, platinum, palladium, etc. then it creates various color tones like white, pink/ rose, green and the seldom found blue, purple and black. It is sometimes called gold color.
Goldsmith:
A person, who is an expert for working with precious metal to create jewelry.
Gram:
Gram is the basic unit of weight of the metric system and generally used to express the weight of jewelry items. One troy ounce contains 31.1035 grams.
Hallmark:
A hallmark is an official mark (or a series of marks) stamped onto a precious metal that indicates the fineness of the metal and the manufacturer’s mark. As well as sometimes hallmarks indicate the country and year of manufacturing. Although marks are not officially required in USA but usually they are carried by custom and practice.
Hammered Finish:
A hammered finish is a texture applied to the surface of a metal piece with a hammer to give it a dimpled look. A hammered texture gives impression of a series of small depressions in the metal. This finish is varied from light to deep hammering texture and usually increases the size of the metal piece.
Hand Made:
Hand made jewelry is created completely by hand and only some hand tools are used for this.
High Polish Finish:
High polish finish is a super shiny and smooth polish applied to a metal surface that gives a highly reflective and mirror-like finish.
Inlay:
This term refers to a decorative feature of an item of jewelry. An inlay is a piece of material (usually stone or glass) that is partially embedded in another material (usually metal) and these two materials make a level surface.
Karat:
Karat is the American spelling of carat which is now only used for gold or gold alloys weight whereas English spelling carat is used in respect of weight of diamonds or other gemstones. Karat is always based on pure 24 karat gold and if a jewelry item contains 18 karat gold that means it has eighteen parts pure gold and six parts other metal alloys. Karat is also used in its abbreviated ‘kt’ form.
Lost-Wax Casting
This is one of the most commonly used casting techniques. Under this casting method, an object is made of wax and coated in clay. When the clay is fired, the wax melts and is drained away or evaporates leaving an exact impression of the object in the hardened clay, which is then filled with molten metal.
Malleability:
Malleability is the physical property of metal that allows it to be hammered, rolled, compressed and stretched. Gold is the most malleable of all metals.
Matte Finish:
A matte finish, also known as a brushed finish, is a texture applied to metal surface, which gives a dull and non-reflective finish. Matte finish is achieved either by a chemical process or by using an abrasive material to scratch the top layers of the piece.
Metal:
Metal is a solid mineral element that usually has a shiny surface and generally a good conductor of heat and electricity, and can be melted or fused, hammered into thin sheets, or drawn into wires. Common metals include bronze, copper and iron whereas gold, platinum and silver are considered as precious metals and used for making jewelry.
Milgrain:
It is a decorative technique in which a beaded design is impressed into the metal by using a special engraver’s tool.
Mirror Finish:
A highly reflective and mirror like finished surface with no visible abrasion pattern.
Mold:
Mold is the hollow form into which molten metal is poured to solidify and then ejected or broken out to get a fabricated jewelry part. It is made from a refractory material either for temporary use or for permanent use.
Ore:
An ore is a group of rocks containing valuable minerals that can be extracted.
Ounce:
A unit of weight. For precious metals, an ounce means a troy ounce which is equal to 31.1035 grams.
Overlay:
Overlay is a type of jewelry decorative technique that involves two flat metal pieces. The top piece is highly polished whereas the bottom layer is darkened with oxidation to provide good contrast when the two pieces are soldered together.
Oxidation:
Oxidation is a chemical process in which a metal is blackened as a reaction to oxygen.
Palladium:
Palladium is a member of the Platinum group metal and it is lighter and less expensive than platinum. Palladium is usually mixed with yellow gold to create white gold.
Patina:
The change in an object’s surface resulting from natural ageing due to oxidation and wear.
Pennyweight:
Pennyweight, usually shortened by dwt, is an American unit of weight for gold. One pennyweight equals 24 grains or 1/20 of a troy ounce. Also a pennyweight is equal to 1.5552 grams.
Pink Gold:
Pink gold, also known as rose gold, is alloyed with copper, and at times possibly even with silver. The proportions are about three parts of 24-karat gold to one part of copper.
Plating:
Plating is the technique to cover or coat a thin layer of a metal to another metal surface mainly for the decorative purposes.
Platinum:
Platinum, an extremely rare and expensive metal, is a silvery gray precious metal often used for setting or mounting high quality diamonds and gemstones. Platinum is a strong, durable and dense metal which is valued for its white color and purity
Plumb Gold:
It is a term used to describe gold jewelry that contains the precise amount of gold in the alloy that the karat mark indicates. A jewelry piece with 18kt plumb gold means that the gold will be at a minimum 18 parts gold mixed with 6 parts alloys.
Polish:
In terms of metal, polish is considered as smoothness of the surface of a metal object in which optical reflection is maximized
Polishing:
Metal polishing is the process of rubbing a metal piece to make it smooth and shiny as well as reduce the appearance of flaws.
Porosity:
Porosity refers to the areas of the mold that absorbed some of the casting material and leaves the cast object with a rough, granular surface.
Precious Metal:
A precious metal is a metal with rare metallic chemical element. Gold, platinum and silver are widely traded and considered as precious metals due to their rarity, beauty and physical properties. Precious metals are less reactive than most elements, have high luster, and have higher melting points than other metals.
Rhodium:
Rhodium is a noble metal, from the platinum family, with a whitish gray appearance. Rhodium, in raw natural state, comes in liquid state and in jewelry industry, it is very popular plating metal which gives very smooth, shiny and expensive look, just like platinum, to a metal piece.
Rhodium Plating:
In this process, rhodium is applied through the electroplating process to base metals like gold, sterling silver or some other metal alloy. This rhodium plating gives silver tone finish, which is darker than a silver plated finish and darkens with time rather than tarnishing like silver plate. Rhodium plating is virtually identical to Platinum but on a fraction of the cost and often it is used on fashion rings and brooches.
Sand Blasting:
Sand blasting refers to the process of cleaning, smoothing or etching a hard surface by forcing very fine bits of solid material across that surface at high speeds.
Sating Finish:
Satin finish is a texture of a metal surface that is in between matte finish and a brilliant one. In this finish, a series of tiny parallel lines are scratched onto a metal surface with a wire brush or polishing tool to produce texture. This finish gives impression of a soft, pearl-like luster instead of a bright polish.
Scoring:
A technique of using a tool to engrave a groove or furrow into the flat surface of the metal.
Silver:
Silver has been known and used for thousands of years and it is considered as one of the three precious metals along with gold and platinum. Pure silver is very soft metal with its lustrous white color. Silver is used as jewelry metal well before the development of white gold alloys, and before platinum could be isolated. It is normally stable in pure air and water but tarnishes when exposed to ozone, hydrogen sulfide or sulfur. The chemical symbol for silver is Ag.
Silver - Sterling:
A mixture of 15%.5% of pure silver and 7.5% of copper is known as Sterling Silver. Pure silver is alloyed with copper to give strength and durability. It is one of the most familiar and used forms of silver alloys.
Soldering:
Soldering is a technique, used by jewelers, in making and repairing jewelry. By using this technique, two or more metal pieces are joined by applying a molten metal or metal alloy that has a lower melting point than the two metals being joined. This molten metal forms a bond when cooled and solidified. Soldering is also used in adding findings or links in a metal piece.
Solid Gold:
As per the rules of the Federal Trade Commission, the term ‘solid gold’ can be used for items which are not hollow and contain at least 10 karat or finer gold.
Stamping:
Stamping is the process of cutting or embossing a mark on metal sheet with a punch or a die.
Tarnish:
A dull metal finish or luster due to its exposure to air or dirt that discolors the surface of metal as well as due to reaction between metals and other chemicals which discolors the surface, particularly silver which reacts with sulfur. Tarnish is a form of corrosion.
Troy Ounce:
It is a unit for measuring the weight of precious metal. One troy ounce equals 31.1035 grams or 480 grains (20 pennyweights (dwt) each of 24 grains)or 1.09711 avoirdupois ounces.
Tungsten:
In jewelry industry, Tungsten is a fairly new metal which often used for wedding bands. It is four times harder than titanium and resistant to corrosion.
Two-Tone:
A piece of jewelry that either uses both white and yellow metals or uses two different tones of same metal.
Vermeil:
Vermeil refers to gold plating, with at least 10-karat gold, onto the surface of sterling silver. The finishing looks are very similar to pure gold jewelry and very hard to differentiate.