References & Recommended Reading

Books for Your Gem Journey:

Vedic Astrology:
Books:
Check out AstroAmerica's selection of Vedic gem books with helpful comments. The main Vedic catalog is vast; one gets an idea of just how complex Vedic astrology is by looking through these titles.

Other titles available on Amazon.com are below:
The Healing Power of Gemstones: In Tantra, Ayurveda, and Astrology by Harish Johari
Good starting point for exploring gemstones in Vedic astrology; contains the rituals, mantras, and talisman instructions for all the planetary gemstones. Also contains instructions for making gemstone healing pastes/medicines as per the ancient texts. (This book is included for reference purposes only!!! Not responsible for gem elixers gone awry!!! I personally would not ingest anything of this type >_<)
The Ascendant: The 108 Planets of Vedic Astrology by Sam Geppi
Focuses on the 9 planets through the ascendant signs.
Ancient Hindu Astrology for the Modern Western Astrologer by James T. Braha
Title explains it all.
Science of Light: An Introduction to Vedic Astrology by Freedom Tobias Cole
A good intro book like the one below if you are interested in Vedic astrology and are just getting started.
Light on Life: An Introduction to the Astrology of India by Robert Svoboda
Highly rated, comprehensive intro book on Vedic astrology; you might want to look at this book first if you are just getting started.
How to Practice Vedic Astrology: A Beginner's Guide to Casting Your Horoscope and Predicting Your Future by Andrew Bloomfield
Includes sample charts and readings of famous people.
The 27 Celestial Portals by Prash Trivedi
Fascinating book about the nakshatras or lunar mansions in Hindu astrology.
Three Hundred Important Combinations by B. V. Raman
The 300 main yogas (planetary combinations) are discussed in this book. FYI, the traditional Vedic text that discusses the yogas is called the Jatakalankara. I found a modern English text based on it here. You can download a translation of the original Jatakalankara (along with a lot of other texts!) from the Hindu Temple of Greater Cincinnati.
Planets in the Signs and Houses: Vedic Astrologer's Handbook Vol. II by Bepin Behari
Part of a reference book style series. Keep in mind that traditional horoscope interpretations tend not to be coated in sugar :)
Stone Lore and Metaphysical Properties:
Take metaphysical lore with a grain of salt; individual stones may vary in their temperaments. A lot of new age books tend to overstate the positives. There are just some rocks out there that don't want to be prodded at by humans (*cough* cursed stones) :)
Books:
Love is in the Earth by Melody
This may be the most well-known of the crystal books out there, covering pretty much every stone. If you have some kind of rare mineral, it's probably in here.
The Crystal Bible by Judy Hall
Comprehensive crystal bible covers metaphysical properties of over 150 stones in full color. Judy Hall has many crystal books out, but The Crystal Bible is the bestseller.
The Book of Stones by Robert Simmons & Naisha Ahsian
Has full color photographs and covers a great amount of stones. Comments on each stone from 2 authors. 
Cunningham's Encyclopedia of Crystal, Gem & Metal Magic by Scott Cunningham
A good starter reference book on crystal lore.
Curious Lore of Precious Stones by George Kunz is a classic text on the folklore, superstitions, and symbolism of precious stones. Kunzite is named after George Kunz, highly influential mineralogist and former vice president and gemologist of Tiffany & Co. This book was written in 1913 and is now in the public domain. Free download from Google Books or Archive.org. Also available in print on Amazon.com.
Gemlore: Ancient Secrets and Modern Myths from the Stone Age to the Rock Age by Diana Morgan
Thoroughly researched book on gem lore and uses throughout history.
Stone Empowerment by Jane Hightower
I personally have not read this book but read much about it. This book covers descriptions, healing, and uses of stones, focusing mainly on healing.

Daoist Mineral Magic by Jerry Alan Johnson
This book covers much of what other gemstone books cover but with Daoist mysticism, Feng Shui and more. The gem descriptions include how to recharge each type of gemstone. 

Also of interest: 
Ring Shui: Move Your Rings, Change Your Life - how wearing rings on certain fingers can change your outlook and vibrations.
Ellen Steiber's fantasy novel, A Rumor of Gems, is based around gem lore. She has a page of gem properties here.

Scientific Reading:
Gem identification, mineralogy, etc.
Books:
Gem Identification Made Easy: A Hands-on Guide to More Confident Buying and Selling by Antoinette Leonard Matlins
My favorite gem id book; has a useful chart on gem fluorescence. I usually check my gems with a blacklight first. This is all around one of the best starter guides I've come across for gem identification (and unfortunately, there aren't many books like this out).