It is made of marble and very tall and round, like a tower. It is mostly used for scrying purposes. Niklaren Goldeye uses the height to scry the future, Trisana Chandler uses it to be closer to the skies and her weather. It is where Tris first learned to scry the winds, as well as use the winds to lift her to the top of the tower.
Phakomathen is located in the wealthier part of Tharios, near Heskalifos, the university.
The building only appears in Shatterglass.