ERS201H5 Lecture Notes - Lecture 3: Auguste Bravais, Crystal System, Monoclinic Crystal System
Document Summary
The three directions are labeled a, b, and c, unless symmetry makes them equivalent. The vertical is labeled c except in the isometric system where all axes are equal. This is a geographical representation of the relationship of the morphology of crystals and the choice of crystallographic axes. Next lecture: physical properties of minerals and hand sample identification: chapter 2 (pp. September 15th, 2014: 1/100,000,000 cm, i. e. sulfur: B = 12. 87 c = 24. 49 . Axial ratio (expressed as a:1:c: a/b : b/b : c/b = 0. 813:1:1. 903, (tetragonal, hexagonal 1:c) structure. Can be measured on natural crystals and by x-ray determination of crystal. Aa plane become: 1 , b, c the plane a"a" (which is parallel to aa but intersects the a axis at two unit lengths would have intercepts: 2a, b, c. Bb plane (which is parallel to the a and c axes and intersects the axis at unit distance) has intercepts: a, 1b, c.
