The quality of gold is measured in units called
karats, abbreviated "k" or possibly "kt", and usually
range from 24k to 10k. 24 karat gold is pure gold, though most jewelry is not made
from this since it is too soft. To make the gold more strong, materials are added
to it such as copper, nickel, silver, and zinc to create an alloy. After the gold
has been mixed with other materials, the amount of gold is reduced, so 18 karat
gold contains approximately 75% gold, 14 karat gold is about 58.5% gold, and 10
karat gold has about 41.7% gold in it. Nothing less than 10 karat gold can be legally
sold as gold jewelry or called gold in the United States.
| Karats |
Karat mark |
European marking |
Percentage of pure gold |
| Twenty-four karat |
24K |
999 |
99.9% |
| Eighteen karat |
18K |
750 |
75.0% |
| Fourteen karat |
14K |
585 |
58.5% |
| Ten karat |
10K |
417 |
41.7% |
Yellow gold more closely resembles the actual color
of gold and is usually an alloy of silver and copper. White gold looks like platinum
and is usually an alloy of nickel, zinc, and copper. Nickel is sometimes substituted
for another mineral in white gold, as some people may be allergic to nickel.
Since gold must be alloyed to other materials when making it into jewelry, gold
is able to come in various colors as well, such as green, pink, or rose.
| Gold Color |
Common Alloy Materials |
| Yellow Gold |
Copper, Silver |
| White Gold |
Copper, Nickel, Zinc |
| Rose / Pink Gold |
Copper |
| Green Gold |
Copper, Silver, Zinc |
Sterling silver is made up of 92.5% pure silver
and 7.5% alloy material, such as copper, to provide extra strength, since pure silver
is generally too soft to make jewelry out of. Any jewelry that is called silver
must contain at least 92.5% pure silver.
The size of gemstones, including diamonds, are measured
in units called carats, abbreviated "ct". One
carat weighs about 200 milligrams, or 0.2 grams, and 142 carats weigh about one
ounce. The size of gemstones may also be measured in units called
points. Often, the larger the size of the stone, the more valuable
it is.
A Carat,
abbreviated "ct", is a unit of measurement for the size of gemstones
and is equal to 100 points. A
Karat, abbreviated "k" or possibly
"kt", is a unit of measurement for gold quality with
24 karats being pure gold and 10 karats being the lowest legal limit for selling
an item as gold jewelry in the United States. A Carrot is a vegetable whose orange,
conical shaped roots are eaten for their nutritional value and has no relation to
jewelry whatsoever.
A point, abbreviated "pt", is 1/100th of a
carat. Therefore, a 100 point size gemstone would
be equal to 1 carat, and a 50 point gemstone would be 1/2 carat in size.
The Total Weight is calculated by adding up all
the stones in a jewelry piece. For example, a jewelry piece containing one 1 carat
stone and two 1/2 carat stones would have a Total Weight of 2 carats.
There are many shapes that a gemstone may take,
but some of the most common are round, oval, pear, heart, marquise, radiant, emerald,
princess, baguette, and trillion. Here is a drawing of these common shapes which
gemstones are cut into:

Note: Birthstone lists may vary from jeweler
to jeweler.
| Month |
Color |
Stone |
Additional Stones |
| January |
Dark Red |
Garnet |
|
| February |
Purple |
Amethyst |
|
| March |
Pale Blue |
Aquamarine |
|
| April |
White / Clear |
Diamond |
White Topaz |
| May |
Bright Green |
Emerald |
Green Tourmaline |
| June |
Cream |
Pearl |
Moonstone, Alexandrite |
| July |
Red |
Ruby |
|
| August |
Pale Green |
Peridot |
|
| September |
Deep Blue |
Sapphire |
|
| October |
Variegated |
Opal |
(Pink) Tourmaline |
| November |
Yellow |
Citrine |
Yellow Topaz |
| December |
Sky Blue |
Blue Topaz |
Turquoise, Blue Zircon, Tanzanite |
|