Gold Coated
Many gold-coated
aricles are also used as substitutes for solid karat gold. The
thickness of the coatings are often expressed in millionths of
an inch, or microinches, and the table below provides a way to
translate between these and other measurement
units.
Thickness
Equivalents |
1 millionth inch (microinch) |
=
|
.0254 micron |
1 thousanth inch (mil) |
=
|
25.4 microns |
1 millionth meter (micron) |
=
|
39.37 microinches |
1 millimeter |
=
|
39.37
mils |
|
Following are the definitions of various gold-coated
articles which are sometimes used in place of solid
karat gold.
Gold Filled: also
called gold overlay, a layer of at least 10-karat gold
permanenetly bonded by heat and pressure to one of more
surfaces of a supporting metal, then rolled or drawn to a
prescribed thickness. The karat gold must be at least 1/20 by
weight of the total meta content.
Rolled Gold Plate: Material consisting of a layer of plating of 10-karat gold or
better which is mechanically bonded to a base metal. The karat
gold content may be less than 1/20 but must be properly
identified by weight in terms of total metal content.
Gold Electroplate: A
coating of at least 10-karat gold or gold alloy plated on a
base metal by electrolysis. The gold plating must be at least
seven-millionths of an inch thick. Electroplating is widely
used in the electronics and aerospace industries.
Gold Wash or Gold
Flash: A film of gold less than seven-millionths of
an inch thick, electroplated on a base metal.
Vermeil: Sterling
silver coated or plated on all significant surfaces with gold
or gold alloy of not less than 10-karat fineness.
Purity
The purity
of gold articles may be described in three ways:
Percent, meaning parts of gold per 100
Fineness, meaning parts of gold
per 1,000
Karat, meaning parts of gold per 24. Not to be confused with the
carat, equaling a fifth of a gram, which is used to state
the weight of a gem stone. The following table shows the
examples of these value for some common grades of
gold.
| Percent
Gold |
European
System |
Karat
System |
|
|
100% |
=
|
1000 fine |
=
|
24 karat |
91.7% |
=
|
917 fine |
=
|
22 karat |
75.0% |
=
|
750 fine |
=
|
18 karat |
58.3% |
=
|
583 fine |
=
|
14 karat |
41.6% |
=
|
416 fine |
=
|
10
karat* |
|
|
*The minimum amount of gold that a product
can be composed of and carry the label "gold",
according to the U.S. Federal Trade Commission
"Guides to the Jewelry
Industry." |
|
Weight
The weight of gold or gold articles is usually
expressed in troy ounces. The table below provides a
convenient way to translate between troy ounces and other
units of weight.
1 troy ounce |
= |
20 pennyweight |
1 troy ounce |
= |
1.097 ordinary ounces |
1 troy ounce |
= |
480 grains |
1 troy ounce |
= |
31.1 grams |
1000 troy ounces |
= |
31.1 kilograms |
1 gram |
= |
.03215 troy ounces |
1 kilogram |
= |
32.15 troy ounces |
1 tonne |
= |
32,151 troy ounces |
1 avoirdupois (ordinary) ounce |
= |
.911 troy ounces |
1 avoirdupois (ordinary) pound |
= |
14.58 troy
ounces |
|
|
![[Most Recent Quotes from www.kitco.com]](http://www.kitconet.com/charts/metals/gold/tny_au_en_usoz_2.gif)
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