Khan Academy
Khan Academy: Gems and Their Creation
A gem is a precious or semiprecious stone that has been cut, polished, engraved, or otherwise altered to be used as a personal insignia for making sealings or as decoration. Often imported from afar, ancient gems were truly exotic, and...
Khan Academy
Khan Academy: Gem Carving Quiz
Test your knowledge of gem carving with this seven-question quiz.
Wikimedia
Wikipedia: Ruby (Gemstone)
This site from the Wikipedia encyclopedia gives a definition and information on hardness, value determination, and natural versus artificial rubies. Links are provided throughout for additional information on related subjects.
Other
Gem Hut: Agate (Chalcedony) Gemstones
Contains general information on agate, including links to information about various varieties. Commercial site, good for pictures of varieties of agate.
Other
Gem Hut: Zircon
This commercial page gives information about the physical properties of zircon, its appearance, and where it can be found. Includes pictures and tables.
Jewelry Central
Jewelry Central: Topaz
This commercial site contains information about the physical and metaphysical properties of topaz, along with where it is found. Discusses the different color variations, and how this gem is enhanced to make it blue.
Jewelry Central
Jewelry Central: Zircon
This commercial site contains information on zircon including its history, physical and metaphysical properties, and where it can be found.
Jewelry Central
Jewelry Central: Onyx
This page gives brief, general information on onyx, including its history, physical characteristics, and metaphysical properties. Commercial web site.
Other
Icga: Emerald
Site provides information on the history of emeralds, their physical properties, and where they can be found. Also provides pictures of emeralds and detailed information concerning them.
Other
Gem Hut: Sky Blue Topaz
A commercial site with a short description of the physical properties of topaz, and pictures of cut and polished stones for sale.