Turbostratic graphite is graphite in which there is quenched rotational disalignment between adjacent graphene sheets, i.e. one sheet is rotated with respect to its neighbor. I suppose this could be considered a crystallographic defect of sorts. How do these turbostratic layers form, and can they possess long range order, such as glide or helical symmetry (e.g. similar to a twisted nematic phase)?
"High-temperature phase transformation and low friction behaviour in highly disordered turbostratic graphite," doi:10.1088/0022-3727/46/39/395305
"Phase Transformation Mechanism of Graphite-Turbostratic Graphite in the Course of Mechanical Grinding," CHEM. RES. CHINESE U. 19(2), 216 (2003)