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What is Gold?
With other numbers of metals
or alloys such as copper or iron pyrite, copying
gold color is easy. They will look just as the
gold as the real 18k gold. So why pick 18k gold?
The answer is easy. Gold does not change in color,
rust or corrode or fade. Gold survives time. Also
gold can be shaped to any size or shapes. However
with gold's flexibility has a drawback. Due to
its flexible nature, gold's strength in minerals
or harness is near the bottom of the chart. Because
of these weaknesses, gold is mixed with one or
more additional metals to make it strong. We call
this alloy; they are usually copper, silver, nickel.
These alloys not only strengthen the gold, but
determine the color of the gold. For example,
yellow gold will contain copper, and white gold
will have nickel, zinc and copper is mixed in.
With these concepts, gold can come in many color
such as pink gold or also know as rose gold, or
purple gold etc.
What does karat means
in 18k?
In mineral community, precious
metals measured in ounces. But this ounce system
is not the system of 16 ounces to a pound which
we are familiar with. Gold is instead measure
what ancient troy standard. This standard is also
used in pharmacists and medical profession today.
Here is an example of weight system.
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1
troy ounce
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=
480 grains
= 20 pennyweights
= 1.097 avoirdupois ounces
= 31.103 grams |
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1
troy pound
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=
12 troy ounces
= 5760 grains
= 240 pennyweights
= 13.164 avoirdupois ounces
= 0.82275 avoirdupois pounds
= 373.236 grams |
Karat in most in English
speaking countries spells in "carat"
but in U.S. carat is used to measure gem stone's
weight such as 1 carat diamond. The word carat
is from ancient time when it was used from carob
plant which was used to measure weight of gemstones.
Carob plant's seed was used for this process.
One carob seed weighted about 200 milligrams.
Now going back to gold,
purity of gold is measure from 1 to 24. 24 karat
(24K) is purest form of the metal. So when you
hear 18k gold, it means 18/24 karat which is 75%
of gold and 25% alloy. More alloy, or lower karat
in gold, gold becomes much more strong.
Gold Marks:
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American
Marking(karatage)
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Pure
Gold content
(Fineness in percent)
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European
Marking
|
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24
K
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100
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1,000
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22
K
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91.6
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916
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20
K
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83
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833
|
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19
K (used in Portugal)
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79.2
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792
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18
K
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75.0
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750
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15
K (seen in antiques)
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62.5
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750
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14
K
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58.3
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585
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12
K
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50.0
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500
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10
K
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41.7
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417
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9
K
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37.5
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375
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Minimum Gold Content
To be called gold, there
are minimum gold content. It varies by where you
are, but in United States, item must be at least
10 K and in England and Canada 9 K and in Italy
and France 18 K
Many Colors of Gold
| Color |
Composition |
| Yellow
Gold |
Gold,
Copper, Silver |
| White
Gold |
Gold,
Nickel**, Zinc, Silver, Palladium |
| Green
Gold |
Gold,
Silver, Copper, Zinc |
| Pink
(Red) Gold |
Gold,
Copper |
** Some people are allergic
to nickel and should not whear white gold which
contains Nickel. Some manufacturers use Palladium
instead of Nickel. White gold which contains Palladium
will be more expensive than yellow gold or white
gold but it will be less expensive than Platinum.
What causes skin discoloration
with some gold jewelry?
Pure gold does not change
in color or tarnish and it won't discolor the
skin. But when alloy is used to mix with gold,
the gold can change and oxidize. Also human's
fat or acids in perspiration can start this change
in gold. It usually gets worse in warm and damp
areas where lots of salt is in the air. Sometimes,
woman's makeup can start the problem.
How to solve discoloration
in gold?
1. Make a habit of removing
jewelry often and cleaning the skin and jewelry.
2. Use soft cloth to wipe and clean jewelry to
remove tarnish.
3. Try to switch to higher gold content jewelry.
When you have discoloration gold problem in 14k
gold, try to switch it to 18k gold.
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