Gyroidal

Gy*roid"al (jī*roid"al), a. [Gr. gy^ros circle + -oid + -al.] 1. Spiral in arrangement or action.

2. (Crystallog.) Having the planes arranged spirally, so that they incline all to the right (or left) of a vertical line; -- said of certain hemihedral forms.

3. (Opt.) Turning the plane of polarization circularly or spirally to the right or left.