Silver atom center in α-quartz

A new paramagnetic center, Afs_Ag?Si, in silver-diffused α-quartz is described and its spin-Hamiltonian parameters are presented. The center is formulated as a silver atom $\text{(S =}\text{1}\text{2}\text{)}$ situated in a c-axis channel, bonded weakly to a normal silicon cation, with four oxygen anions as neighbors. A_Ag?Si is created by X-irradiation and is unstable at room temperature.