Birthstones by Month
January - garnet
February - amethyst
March - aquamarine
April - diamond
May - emerald
June - pearl, moonstone, alexandrite
July - ruby
August - peridot
September - sapphire
October - opal
November - topaz, citrine
December - blue topaz, turquoise, blue zircon, tanzanite
Commercial value of gemstones relative to each other. (I am not convinced of the accuracy of this listing, but it was the only one I found)
1 Ruby
2 Emerald
3 Diamond
4 Blue Star Sapphire Ruby Stars
5 Red Alexandrite
6 Blue Crystal Sapphire
7 Black Opal Blue Opal White Opal
8 Cats Eyes Aquamarine Topaz
9 Peridot Amethyst Tourmaline
10 Lapis Lazuli Turquoise Moonstones
11 Malachite Tigers eye Coral
12 Rhodocrosite Rhodonite Rose Quartz
13 Jaspers Agates Bloodstones
http://www.sobrietystones.com/resources/stonevalues.htm
