There are many books available on this subject. Chief among them are:

The Crystal Bible series by Judy Hall ©

The Book of Stones series by Robert Simmons and Naisha Ahsian ©

Love Is In The Earth series by Melody ©

The Crystal Textbook by S. Roger Joyeaux ©

It is always interesting and instructional to have on hand more than one set, so that one can compare and contrast differing points of view with one’s own meditations. Most often I have found that when I am drawn to a particular stone or crystal, and then look it up in one or more of the books, it fits very well to my needs of the time. A few people have asked me to choose a stone for them, so I give them a choice between two or three. The one they are most drawn to usually turns out to be the best one for their needs.
Of course, there doesn’t have to be a need for a stone or crystal. You can just choose a pendant because you like it! Beauty is its’ own reason.