第二章 宝玉石的性质1.pdf

第二章 宝玉石的性质 第二章 宝玉石的性质 Chapter 2 Nature of Gemstones Chapter 2 Nature of Gemstones 陈炳辉 Chen Binghui Department of Earth Sciences Sun Yat-sen University Contents Section 1 Crystallography of Gemstone Section 2 Mechanical Properties of Gemstone Section 3 Optical Properties of Gemstone Section 4 Other Physical Properties Section 5 Inclusions in Gemstone Section 6 Fashioning Styles of Gemstone 第一节 宝石的结晶学特征 Crystallography of Gemstone 一、 晶体与非晶体 晶体：内部结构原子或离子在三 维定向成周期性重复有序排列的 固体。 石盐晶体结构 A Crystal is a Solid with a structure of regular, repeating, three dimensional arrangement of bonded atoms. • 非晶体：内部结构中原子 或离子无序排布，不能自 发形成几何多面体外形。 Non-Crystalline: Minerals and other materials are said to be non-crystalline, or amorphous, when they lack an overall orderly crystal structure. OBSIDIAN (Volcanic Silica Glass) 二、晶体习性 Crystal Habits 三、对称要素 Symmetric Elements 中心 Center 面 Plane 轴 Axis of symmetry - An imaginary line drawn through the center of a crystal that replicates the exact shape if the crystal is turned to 360 °. 对称面 对称轴 对称中心 四、七大晶系（Crystal Systems) 2 三斜Triclinic ： 无L 或P 单斜Monoclinic：L2和P均不多于1 斜方Orthoclinic：L2和P不少于三个 三方Trigonal ： L3高次轴 六方Hexagonal：L6高次轴 四方Tetragonal ：L4高次轴 等轴Isometric： 3L4 Contents Contents Section 1 Crystallography of Gemstone Section 2 Mechanical Properties of Gemstone Section 3 Optical Properties of Gemstone Section 4