W.Kaminsky, E.Hartmann: Anisotropy of optical activity and Faraday effect in TeO2. Z.Phys.B 90 (1993) 47-50.
The tensor of optical activity of TeO2 was derived with the aid of measurements of the Faraday effect. This technique allows the separation of gyrative effects in crystals having a large birefringence. The natural activity of TeO2 perpendicular to the fourfold axis is about a factor two larger than along this axis. The sign of the tensorial components is related to structural details.