This 13-page booklet focuses on magic associated with stone and earth, although one senses that the writers struggled a little more than they did with its counterpart on Air magic. For instance, some of the spells are more to do with acid than earth. There is a justification for this in the book, and it is, of course, fully consistent with the Pathfinder rules, but it still feels as if the writers felt hat earth itself was a bit too limited.
There are 22 spells in the booklet, and, despite the comments above, in fairness most of them are quite directly to do with the element. Most are directly related to delivering or resisting damage, as one might expect, although there is some more variety at the lower levels. The spells range from 1st to 7th level, and are mostly for druids and wizard/sorcerers, although some are also available to bards, and (at higher levels) to clerics.
The booklet also includes a stone descriptor for spells, which makes a lot of sense, and has certain advantages over the standard earth descriptor. There is a bloodline for sorcerers and a speciality for wizards, as well as a monster template, and rules for a special kind of earth elemental (which one of the spells lets you summon). Clerics get a new domain, but it's really about anti-magic, not earth.
In general, this is a good, well-written rules source, albeit one that strays a little too far from its stated topic at times.
[4 of 5 Stars!]