From publisher blurb:
Unlock new options for the iconic crystalline buddy of the psionics world - the psicrystal from Ultimate Psionics. Whether storing psionic power in the psicrystal, embedding it into a creature, or turning it into a weapon, the psicrystal gains all new options for use in the Pathfinder RPG.
Psionics Augmented: Psicrystals Expanded includes six new advanced psicrystals, eleven new psicrystal-related feats, two new psicrystal related powers, a new aegis customization, a new soulknife blade skill, and an expanded list of psicrystal personalities.
If your psionic character uses a psicrystal, this book is for you!