Gold Measurements
Gold measurements
can be a bit confusing. The weight of gold is measured in troy ounces (1
troy ounce = 31.1034768 grams), but its purity, or "fineness"
has been measured in a few different ways: "parts fine," "%
gold", and karats. (A major point of confusion is between "carat,"
which is a measure of weight for precious stones, and "karat",
which is purity measure for gold. The terms are used distinctly, even if
they have the same derivation.) According
to at least one source, the terms karat and carat derive from Arabic and
Greek words meaning "the fruit of the carob tree." Apparently,
the seeds of the fruit, remarkable for their consistency, were used to
balance the scales used by merchants at ancient bazaars[1].
Karats now refer to the ratio of gold found in a sample. There are 24
karats, so pure gold is 24 karats. The percentage of gold in a piece is
therefore the number of karats/24. Thus 96.5% gold is 23 karat (23.16
to be exact).The legally permissible "karatage" for an item to be called
gold historically has differed from country to country. The US, for example,
permitted 10 karat jewelry to be called gold even though it was well less
than 50% gold.
Notes
- The trouble is, that turns out not to be true, as Lindsay Turnbull
from the University of Zurich, Switzerland, and colleagues found out.
The team collected and weighed 550 seeds from 28 carob trees in Mallorca
and found they are just as variable in weight as seeds from 63 other
species of tree (Biology Letters, DOI: 10.1098/rsbl.2006.0476).So how
did carobs come to be regarded as constant in weight? Turnbull speculates
that people just selected the seeds they wanted to use. To test the
idea, she set up a perception experiment. "People were able to
identify the heaviest seed of a pair even when the difference in weight
was very small, 1/100 of a gram."
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Weight Systems
The Troy system is often used to measure precious metals and gemstones.
1 troy ounce = 480 grains
1 grain = 64.798 91 milligram
1 troy ounce = 31.1034768 grams
24 grains = 1 pennyweight
20 pennyweight = 1 troy oz
12 troy oz = 1 troy lb
The Metric sytem is also used
1 Troy Ounce = 31.103 Grams
1 Pennyweight =1.555 Grams
15.432 Grains =1 Gram
1 Grain = .0648 Grams
Be sure you know the difference between grams and grains! Some unscrupulous sellers will intentionally mislead the public by listing weights with incorrect abbreviations ("g" is for grams and "gr" is for grains).
Abbreviations:
gr= Grains
Gm = Grams
Oz = Ounce
ozt =
Troy Ounces
dwt =
Pennyweight
Kgm =
Kilogram (1000 grams)
One way to do conversions
is using the google
calculator
These sample queries show
how easy it is:
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