A Treatise on Crystallography

adjacent faces adjacent poles angle between normals arcs joining arranged with respect circle cleavable parallel cos PX cos PY cos cot PY crystal meet cube denoted distance dodecahedron equal angles equations faces hkl faces of 100 faces of hkl form bounded form hkl form with inclined forms with parallel h+k+l hemihedral form Hence the crystal holohedral form inclined asymmetric faces inclined faces indices h intersect inverse form Let the symbols meet the surface nearest pole number of faces octahedron odd number parallel faces parameters perpendicular poles of 100 poles of hkl prismatic system projection be divided ratios rhombohedral system sin PQ sin QR sphere of projection symbol hkl symmetric faces symmetrically arranged twin axis twin crystal u v w Whence zone zone-circle ΟΥ