The structure of high quartz was determined applying the space groups P 6 2 2 (or P 6 4 2) and, under supposition of twinning, P 3 1 2 (or P 3 2 2) at 650° of The Wyckoff structure could be refined to 25% for relative mean deviation C. intensities ( R ∼ 16.2%). Assuming a submicroscopic twinning of low quartz lead to 19,3 mean deviation ( R ∼ 12.6%). Therefore must be assumed that high quartz is submicroscopically twinned according low-quartz symmetry.