Witchipedia.com states that there is little recorded history of lithomancy. Although the earliest recorded mention of the practice is the late 800s, the techniques have been lost. Witchipedia also proivides a suggested technique.
Just for fun, bonus L is Llewellyn. Not a method of divination, but a Mind, Body and Spirit publisher with an online tarot-reading section on their website. Which is fun and also has some lovely artwork.