Note 2945 — BOOK XXXVII. THE NATURAL HISTORY OF PRECIOUS STONES.
John Bostock translation
“Its shape is rhombohedral, and hemihedral in some of its modifications. The planes on the angles between the prism and pyramidal terminations, incline sometimes to the right, and sometimes to the left, and the crystals are termed right and left-handed crystals.”—Dana, System of Mineralogy, Art. Quartz.