Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Making 14k Gold
Name: Jared
Status: student
Grade: 6-8
Location: KS
Country: USA
Date: N/A 


Question:
How is 14 karat gold made? How are the metals chosen, combined, melted, purified, and cooled?



Replies:
Hi Jared,

The "karat" system of identifying the purity of gold is based on pure gold being defined as 24 karat. Thus, 14 karat gold is 14/24ths (or about 58.3%) pure gold by weight. The remaining 41.7% is other metals, generally copper and silver. The ratio of the copper and gold can vary, but usually it is "50-50"; that is, the most common proportions of metals (by weight) used to make 14 karat gold are...

Gold: 58.3%
Copper: 20.85%
Silver: 20.85%

Sometimes the ratio of copper to silver is slightly changed to change the color of the end product. If the percentage of copper is slightly increased, the resulting 14 karat gold will look a little more "rosy" in color. If the percentage of silver is increased, the result will look a little more white or slightly more silvery. To be called 14 karat, the percentage of gold, however, never changes.

The reason for adding copper and silver to the gold is that pure gold is very soft and easy to damage in jewelry. Adding copper and silver results in a much harder alloy, and also reduces the cost. The additional metals (copper and silver) are chosen because they result in a harder alloy, that still looks like gold.

You asked how 14 karat gold was made. That part is easy! The three separate metals are weighed and put into a crucible, then heated (usually over a gas flame). Since the three separate metals are already purified, by their individual refining processes, there is no need to purify the result when they are melted together. Once the gold, copper and silver are melted together, the crucible is set aside to cool. That's all there is to it!

Regards,

Bob Wilson



Click here to return to the Material Science Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory