This free online course is the first to be reviewed and given its own special page here, because I found it extremely helpful as an amateur gem collector.  It is the first time I've seen a free resource that focussed on the features and real beauty of stones regardless of their market value.

I always loved rubies, but this course taught me to truly appreciate them for the tiny miracles of nature that they are.  Both my collection and my jewelry art became more beautiful as a result of the information here.  Dr. Smigel is a wonderful instructor, and a true expert in her field.

~Nicole Lasher

Go to Introduction to Gemology!

• Lesson 4: Optical Properties of Gems 
• Lesson 5: Magnification and What it Reveals 
• Lesson 6: Optical Phenomena in Gemstones 
• Lesson 7: Gem Fashioning 
• Lesson 8: Gem Enhancement 
• Lesson 9: Synthetics and Simulants 
• Lesson 10: Gem Formation 

Essays on specific gems:

• Lesson 1: Chrome Diopside, Jet, Benitoite, Aquamarine, Rock Crystal Quartz, Red Beryl, Coral, Ivory, Danburite 
• Lesson 2: Labradorite, Mexican Opal, Chrysocolla Chalcedony, Morganite, Charoite, Tsavorite 
• Lesson 3: Moldavite, Drusy Gems, Fire Agate, Nephrite, Botryoidal Gems, Hardness, Jadeite, Specific Gravity 
• Lesson 4: Pyrite, Andalusite, Peridot, Ruby, Rhodocrosite, Dispersion, Tanzanite, Fluorite, Chrysoprase 
• Lesson 5: Included Quartz, Rubellite Tourmaline 
• Lesson 6: Aventurescent Gems, Chatoyance, Star Stones, Color Change Stones, Iridescent Gems, Cat'seye Stones 
• Lesson 7: Considering Faceting, Less Common Organic Gems 
• Lesson 8: Tanzanite, Zircon, Blue Topaz, Iolite, Oregon Sunstone, Spinel, Uvarovite Garnet 
• Lesson 9: Synthetics, Simulants and Fakes, Assembled Stones, Natural Pearls, Freshwater Cultured Pearls, Saltwater Cultured Pearls 
• Lesson 10: Sugilite, Malachite, Turquoise, Fossil Plants as Gems, Birthstones, Lapis Lazuli, Meteorites as Gems