Jewelry Size and Weight Comparison Guide
Jewelry sizes are often specified in millimeters. For instance, the width of a ring might be given as 6mm, but not as it's English equivalent of .23622 inches. For items which use metric dimensions and weight, we always specify the corresponding approximate measurement in inches and ounces, too (see the specification table that is at the bottom of each item's web page). But even then, it is hard to visualize sizes, so use the illustration above for dimensional and weight comparisons. For instance, a 6mm-wide wedding band would be about the same width as a stack of four pennies or three nickels.
See also this
handy chart and calculator to convert between millimeters and inches.
Authored by:
William C. (Bill) Long