Are you confused by the myriad of hallmarks associated with Gold, Silver and Platinum?  Do you know why the most important hallmark that you can look for is the quality mark of the metal?  Do you ever wonder what is meant by gold filled, gold plated and vermeil?  If so, this guide is written with you in mind.  Whether you are new to metals or a seasoned professional who simply wants to have something handy - this guide is here to help.

PRECIOUS METAL:  a rare metallic chemical element of high, durable economic value.  Chemically, precious metals are less reactive than most elements, have a high luster and have a higher melting point than other metals.  The best known precious metals are Gold, Silver and Platinum (which includes all the Platinum Group Metals [PGM]:  Ruthenium, Rhodium, Palladium, Osmium and Iridium).

A given metal is precious if it is rare.  If mining or refining processes improve, or new supplies are discovered and exploited, the value of such a metal declines.  For example:  aluminum.  When aluminum was first discovered it was extremely difficult to separate from the ore it was part of and one of the most difficult metals on earth to get, despite the fact that it is one of the most common.  For a while, aluminum was more valuable than gold!

GOLD:  is a chemical element in the periodic table that has the symbol Au and atomic number 79.  A soft, shiny, yellow, heavy malleable transition metal, gold does not react with most chemicals but is attacked by chlorine, fluorine and aqua regia (a mixture of hydrochloric acid and nitric acid, which will dissolve gold).  The metal occurs as nuggets or grains in rocks and alluvial deposits. 

Pure gold is too soft for ordinary use and is hardened by alloying it with silver, copper and other metals.  In addition, adding metal alloys will yield different colors: copper a reddish color, iron a green color, aluminum a purple color, platinum a white color and natural bismuth together with silver produces a black color.  Gold is most commonly alloyed with copper.  However, native gold (the occurrence of gold in a pure state in nature) contains usually eight to ten percent silver, but often much more - alloys with a silver content over 20% are called electrum.  As the amount of silver increases, the color becomes whiter.  [Not to be confused with electrolytic gold which is very pure gold (999.9 fine) produced by a refining process employing electric current.]

(Native Gold Nuggets)

Gold is measured in karats (kt) when selling it in the form of jewelry.  While pure gold is 24kt (or 1/24 part of pure gold by weight), gold used for jewelry is more commonly sold in 18kt, 14kt, and 10kt.  The lower the "kt" the more copper or silver has been alloyed into the gold.  Gold purity may also be described by its fineness, which is the amount of pure gold in parts per thousand.  For example, a gold ring hallmarked 585 has 585 (58.5%) parts fine gold and 415  (41.5%) parts of another base metal.  There is an age old tradition of biting gold in order to test its authenticity.  While this is certainly not a professional way to examine gold, the bite test should score the gold because gold is considered a soft metal according to the Moh's scale of mineral hardness (2.5 to 3).  The purer the gold the easier it should be to mark.  However, painted lead can cheat this test because lead is softer than gold.

QUALITY MARK:  The Federal Trade Commission requires that all jewelry items sold in the United States as gold shall be described by a "correct designation of the karat fineness of the alloy."  This is commonly referred to as a Quality Mark and is verification that the item being sold is accurately stamped.  No jewelry item less than 10kt may be sold in the United States as gold jewelry.

Karat/QualityMark     Percentage     European/Quality Mark

9                                   37.50%           375 (Great Brittan only)

10                                 41.67%           416

12                                 50%                500

14                                 58.33%           583 or 585

18                                 75%                750

22                                 91.67%           917

23                                 99.75              990 (alloyed w/1% titanium)

24                                 99.99              999 or .99999

Other Gold Terms:

Plumb Gold: Karat weights are usually determined with a small, fractional variance allowed.  Karat gold which has no variance and is exactly the precise fractional karat weight is called "plumb" gold.  This is typically identified with a "P" hallmark.

Gold Filled, Gold Overlay & Rolled Gold Plate:  items so designated can be up to 200 times thicker than the heaviest gold electroplating available today.  These items are created by using heat and pressure to permanently fuse a layer of karat gold over a less costly base metal.  The minimum layer of gold must equal 1/20th of the total weight of the finished item.  The surface layer of karat gold is usually 10kt,12kt or 14kt.  Therefore the item could/should be marked as follows: 1/20 12kt, 14 Karat Gold Filled, 14 Kt. Gold Filled, 14 Kt. G.F., 14 kt Gold Overlay or 14k R.G.P.  This means that 1/20th (or 5%) of its total weight must be 10kt, 12kt or 14kt gold.  The value of gold filled is greater than gold plated because gold filled has an actual layer, not just a microscopic film of karat gold.

Rolled Gold Plate & Gold Overlay: only these two terms are used when the quantity of karat gold is less than 1/20th of the total weight of the finished metal item.  It must be identified with a fraction mark indicating the quantity of gold.  A typical legal marking might then appear as 1/40th 12kt R.G.P or 1.40th 12kt Rolled Gold Plate.

Gold Plating: is a method of depositing a thin layer of gold on the surface of another metal, usually copper or silver, by chemical or electrochemical means.  The layer may be no less than 10kt gold and the thickness must be equivalent to one-half micron or 20 millionths of an inch.  It must be designated as Gold Plate, Gold Plated or G.P.

Gilding: is the mechanical or chemical affixing of thin gold foils on the surface of objects.

Gold Electroplate, Gold Flash or Gold Washed: means a gold coating that is 10k or better and at least 0.000007 inches thick.  A variant, "heavy gold electroplate" (H.G.E.P) is at least 0.0001 inches thick.

Vermeil: (pronounced "Vur-MAY") is the official industry designation for a heavy gold electroplating over a base sterling silver material.  A minimum thickness of 100 millionths of an inch or 2.5 microns of fine gold must be deposited before it can be marked or sold as vermeil.

PLATINUM: is a chemical element in the periodic table that has the symbol Pt and atomic number 78.  A heavy, malleable, ductile, grey-white transition metal, platinum is resistant to corrosion and occurs in some nickle and copper ores along with some native deposits.  The metal appears silver-white when pure, and firm.  Platinum does not oxidize in air at any temperature, but can be corroded by cyanides, halogens, sulfur and caustic alkalis.  This metal is insoluble in hydrochloric and nitric acid, but does dissolve in aqua regia.

Naturally occurring platinum and platinum alloyed with iridium and platiniridium is found in areas of the Americas.  Arsenide (aka sperrylite) is a major source of platinum associated with nickel ore deposits.  The mineral cooperite contains platinum along with palladium and nickle.  South Africa is the largest producer of platinum in the world where platinum occurs in alluvial deposits. 

(Natural Platinum Nuggets)

The FTC allows the following abbreviations for each of the PGM to be used for quality marks on items:  '"Plat." or "Pt." for Platinum; "Irid." or "Ir." for Iridium; "Pall." or "Pd." for Palladium; "Ruth." or "Ru." for Ruthenium; "Rhod." or "Rh." for Rhodium; and "Osmi." or "Os." for Osmium.'

Platinum     Percentage  Quality Mark

850               85%             850 Plat. or 850 Pt.

900               90%              900 Plat. or 900 Pt.

950               95%              "Platinum" no qualifying statement*

999               99.9%            "Platinum" no qualifying statement*   

* Jewelry items which contain less than 50% pure platinum cannot be marked "Platinum". 

However an item containing at least 950 parts per thousand PGM of which at least 500 parts per thousand is Platinum can be marked "Platinum" so long as each PGM is preceded by a number indicating the amount of parts per thousand of each PGM.  For example:  600Plat.350 Irid. or 600Pt.350Ir; 550Pt.350Pd.50Ir. or  550Plat.350Pall.50Irid.

SILVER: a chemical element in the periodic table that has the symbol Ag and atomic number 47.  A soft, white, lustrous transition metal, it has the highest electrical and thermal conductivity of any metal and occurs in minerals and free form.  Silver is a very ductile and malleable (slightly harder than gold on the Moh's scale of hardness) metal with a brilliant white metallic luster that can take a high degree of polish.

Pure silver is stable in pure air and water, but does tarnish when it is exposed to ozone, hydrogen sulfide, or air that contains sulfur.  Silver is found in native form, combined with sulfur, arsenic, antimony or chlorine and in various ores such as argentite and horn silver.  The principal sources of silver are copper, copper-nickle, gold, lead and lead zinc ores.

(Natural Silver)

Commerical grade silver is at least 99.9% pure silver and purities greater than 99.999% are available.  Fine silver (99.9% pure) is generally too soft for producing large functional objects, and in Sterling the silver is usually alloyed with copper to give strength while preserving the ductility of the silver and a high precious metal content.  Sterling silver is an alloy of silver containing 92.5% pure silver and 7.5% other metals, usually copper.

Silver   Percentage    Quality Mark

800      80%                .800 used for casting

900      90%                .900 coin silver

925      92.5%             .925 Sterling Silver

950      95%                .950 aka Mexican Silver

958      95.8%             .958 aka Britannia Silver

999      99.9%             .999 aka Fine Silver

I hope you have found this guide to be informative and helpful.  In the event that I have not answered all your questions or I have missed something - please let me know.  I wish you success in your precious metal buying and selling!