Troy Weight Conversion Calculator
This online conversion calculator will convert among different troy units of weight or mass. For broader calculations use the weight conversion calculator and more specific to avoirdupois, the U.S. standard system units, use avoirdupois unit conversions.
Troy system of units is still commonly used for precious metals such as gold, silver and platinum along with gemstones.
References/ Further Reading
The National Institute of Standards and Technology (NIST) - The NIST Guide for the use of the International System of Units - Appendix B, subsections B.8 Factors for Units Listed Alphabetically and B.9 Factors for units listed by kind of quantity or field of science.
Lide, David R., Daniel (Editor-in-Chief). CRC Handbook of Chemistry and Physics, 89th Edition New York, NY: CRC Press, p. 1-28, 2008.
Wikipedia contributors. "Conversion of units" Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited 24 Jun. 2011.