1 carat opal/1 carat ruby
many gemstones (over 3000) and all of them vary in
weight. Custom metal work is required if carat weight is
used to define the size of the piece of jewelry for each
gemstone. This would add a great deal of time and cost in
producing each piece of jewelry. So gemstones and cast
mountings are calibrated to save all of us cost and time.
Why use metric units. See our Gemstone information
pages and view some of the gemstones
MAJOR SOURCES. You
will find many, if not most, gemstone do not come from the United
States. We all know that most countries in the world use
metric units. Gemstones come from many countries so
metric units are used in gemology as well as
jewelry. The best we can
do is to convert to English units as close as possible.
The conversion chart below will help those of us not
accustomed to metric units visualize size.
You can also use our carat conversion
charts to estimate many gemstone weights per mm size.
Carat conversion charts for
(emerald) cut chart,
diamond carat conversion chart
For more diamond information. Visit our "Four
C's diamond grading chart".
Find more gemstone information.
Visit our "Gemstone"