I was just wondering, as I would like to find more information (other then the internet) and add it to my... "collection"  

In my opinion, there is no "best" Crystal Healing book. Each has it's own merit, and it depends on what you are looking for in a book. There are things I agree and disagree with in each book. You take what you want from each and disregard the rest. However I do have several recommendations.

The Illustrated Directory of Healing Crystals: A Comprehensive Guide to 150 Crystals and Gemstones - Good Pictures, Nice description, good beginner's book
by Cassandra Eason

Stones Alive! (More Crystals and New Age) - There are now three volumes, written from the Stones' perspective, quite interesting. I've met the author's and they are wonderful people!!!
by Marilyn Twintreess and Thomas Twintreess

The Book of Stones: Who They Are & What They Teach - A little more comprehensive, good pictures.
by Robert Simmons (Author), Naisha Ahsian (Author), Hazel Raven (Contributor)

Love is in the Earth - Quite comprehensive, you'll find stone references here that are very rare and expensive. The original version has no pictures, so you'll have to use the other picture books for reference (there is a whole series of them). Melody did just come out with a HUGE new book with pictures. My understanding is the book is $100.00, so It is quite an investment.
by Melody

Above all I would use your intuition, and use books as a reference, not as a hard rule.

I have a book called The Crystal Bible

I like the Book of Stones, although I refer to the Crystal Encyclopedia and Love is in the Earth as well.

Below is a list of the books that I have read on crystal healing.  Although I feel that there is no "best" book, they all serve their purpose in different ways.  I recommend reading as many as possible and finding out what seems to resonate with your inner truth.  Good Luck!

Andrews, Ted. Crystal Balls & Crystal Bowls: Tools for Ancient Scrying & Modern Seership. Llewellyn Publications. Woodbury, Minnesota: 2006.

Andrews, Ted. The Healer's Manual: A Beginner's Guide to Energy Healing for Yourself and Others. Llweellyn Publications. Woodbury, Minnesota: 2007.

Baraff, Carol. Gems, Stones, & Metals for Healing & Attunement: A Survey of Psychic Readings. Heritage Publications. Virginia Beach, Virginia: 1987.

Bourgault, Luc. The American Indian Secrets of Crystal Healing. Quantum Publishing. Cippenham, Berkshire, England, Great Britain: 1997.

Bowman, Catherine. Crystal Ascension: Spiritual Growth & Planetary Healing. Llewellyn Publications. St. Paul, Minnesota: 1996.

Bowman, Catherine. Crystal Awareness: Healing, Jewelry, Meditations, Color, & Energy: Ancient Secrets Finally Revealed. Llewellyn Publications. St. Paul, Minnesota: 2000.

Chocron, Daya Sarai. Healing With Crystals and Gemstones. Samuel Weiser, Inc. York Beach, Maine: 1986.

Croxson, Roger C. Teach Yourself: Crystal Healing. Teach Yourself Books. London, Great Britain: 2000.

DaEl. The Crystal Book: Explore the Amazing World of the Quartz Crystal and Its Use as a Tool for Harnessing Mind Energy. The Crystal Company. Sunol, California: 1983.

Dolfyn. Crystal Wisdom: Crystal and Gemstone Directory: A Complete Guide to the New Age Gemstones and Crystals, Listing the Spiritual Attributes of Each Stone: Volume VI. Earthspirit, Inc. California: 1991.

Dolfyn. Crystal Wisdom: More Spiritual Gemstones: Volume IV. Earthspirit, Inc. California: 1988.

Ferguson, Sibyl & Revised & Expanded by Witch Bree. Crystal Ball: Stones, Amulets, and Talismans for Power, Protection, and Prophecy. Weiser Books. Boston, Massachutes: 2005.

Galde, Phyllis. Crystal Healing: The Next Step: Improve Creativity, Heighten Intuition, Use Polished Quartz, Heal Yourself & Others, Learn Color Healing, Make Healing Tools, & Reprogram Yourself for Success. Llewellyn Publications. St. Paul, Minnesota: 1989.

Gardner, Joy. Color and Crystals: A Journey Through the Chakras. The Crossing Press. Freedom, California. 1988.

Gienger, Michael. Healing Crystals: The A-Z Guide to 430 Gemstones. Earthdance Publishing. Forres, Scottland: 2005.

Grace, Kendra. Aromatherapy, Crystals, & Vibrational Healing. Nature's Geometry Publications. Laguna Beach, California: 2006.

Hall, Judy. The Crystal Bible: A Definitive Guide to Crystals. Walking Stick Press. Cincinnati, Ohio: 2003.

Harrison, Stephanie & Barbara Kleiner. The Crystal Wisdom Book: Cast the Crystals for Healing, Insight, and Divination. Journey Editions. Boston, Massachusetts: 1997.

Katz, Michael. Gemstone Energy Medicine: Healing Body, Mind and Spirit. Natural Healing Press. Portland, Oregon: 2005.

Lilly, Sue & Forward by Bernice Watt. Crystal Decoder: Harness a Million Years of Earth Energy to Reveal Your Lives, Loves, and Destiny. Barron's Educational Series, Inc. Hauppauge, New York: 2001.

Lilly, Sue, Simon Lilly, Stella Martin, Josephine Winter, & Gill Hale. Crystals, Colour, & Chakra: Healing and Harmony for Body, Spirit, and Home: Learn to Harness the Transforming Power of natural Energies with Practical New Age Techniques and Over 1000 Stunning Photographs and Artworks: Learn How to Energize Every Aspect of Your Life - at Home, at Work, Your Health, Your Mental Well-being and your Relationships with Everyone Around You. Lorenz Books. London, England, Great Britain: 2006.

Mason, Henry M. The Seven Secrets of Crystal Talismans: How to Use Their Power for Attraction, Protection & Transformation. Llewellyn Publications. Woodbury, Minnesota: 2008.

Megemont, Florence. The Metaphysical Book of Gems and Crystals. Healing Arts Press. Rochester, Vermont: 2003.

Melody. Love is in the Earth: A Kaleidoscope of Crystals: Updated: The Updated Reference Book Describing the Metaphysical Properties of the Mineral Kingdom. Earth Love Publishing House: Wheat Ridge, Colorado: 2005.

Melody. Love is in the Earth: Kaleidoscopic Pictorial: Supplement A: An Extension of the Reference Book Describing the Metaphysical Properties of the Mineral Kingdom. Earth Love Publishing House: Wheat Ridge, Colorado: 2004.

Melody. Love is in the Earth: Kaleidoscopic Pictorial: Supplement Z: An Extension of the Reference Book Describing the Metaphysical Properties of the Mineral Kingdom. Earth Love Publishing House: Wheat Ridge, Colorado: 1998.

Melody. Love is in the Earth: Laying-On-Of-Stones: The Journey Continues. Earth Love Publishing House. Wheat Ridge, Colorado: 1992.

Melody. Love is in the Earth: Mineralogical Pictorial: Treasures of the Earth: Designed, Directed, & Arranged by Melody: Primary Photography by Jim Hughes. Earth Love Publishing House. Wheat Ridge, Colorado: 2004.

Moorey, Teresa. Your Crystal Code: Find Out How to Choose, Interpret and Use Your Personal Crystals. Godsfield Publishing. Heron Quays, London, Great Britain: 2006.

Permutt, Philip. The Crystal Healer: Crystal Prescriptions That Will Change Your Life Forever. Cico Books. New York, New York: 2007.

Peschek-Bohmer Ph.D., Flora &  Gisela Schreiber. Healing Crystals and Gemstones: From Amethyst to Zircon: A Comprehensive Listing of the Therapeutic Uses and Healing Effects of the Most Important Crystals and Gemstones. Konecky & Konecky Publishing. Munich, Germany: 2003.

Richardson, Wally, Jenny Richardson as Channeled Through Lenora Huett. Spiritual Value of Gem Stones. DeVorss & Company, Publishers. Marina del Rey, California: 1980.

Rosen, Brenda. Crystal Basics: How to Use Crystals for Wellbeing and Spiritual Harmony. Hamlyn Publishing. Heron Quays, London, Great Britian: 2007.

Scott, Martin J. & Gael Mariani, Forward by Patty Smith-Verspoor. Crystal Healing for Animals. Findhorn Press. Forres, Scottland: 2002.

Simmons, Robert & Kathy Warner with an Introduction by Jean Houston. Moldavite: Starborn Stone of Transformation. Heaven & Earth Publishing LLC. East Montpelier, Vermont: 2004.

Simmons, Robert & Naisha Ahsian with Contributions by Hazel Raven. The Book of Stones: Who They Are & What They Teach. Heaven & Earth Publishing LLC. East Montpelier, Vermont: 2008.

Virtue Ph. D., Doreen & Judith Lukomski. Crystal Therapy: How to Heal and Empower Your Life with Crystal Energy. Hay House, Inc. Carlsbad, California: 2005.