whats the different of cleavage and fracture

whats the different of cleavage and fracture

你好这位朋友,cleavage和fracture是医学上有关骨质等身体组织断裂的两个容易混淆的概念.国外众多医学院官网和教材对此都有说明,在此我引用如下.
先来个简单的区分：
Cleavage -- splits easily along flat surfaces; splits but along its weaker zone
Fracture -- is smooth and curved or jagged with sharp edges
再来个细节说明：
Cleavage occurs when a rock breaks along smooth planes that are parallel to areas in which the mineral has weak bonds.By contrast,rocks are said to fracture if they break irregularly,because the mineral does not form planes of weakness.
Cleavage can occur in several different ways.Some minerals,such as gypsum and muscovite,only exhibit cleavage in one plane.Some minerals,such as halite,cleave to produce cubic particles.This occurs because the rock cleaves in three separate directions and each of the directions is oriented 90 degrees away from the others.Calcite,by comparison,cleaves at angles of 120 degrees and 60 degrees,producing rhombohedral shapes.Quartz does not exhibit cleavage at all,as it fractures irregularly.
Some minerals exhibit perfect cleavage,in which no rough surfaces are produced at all.Others only exhibit good cleavage.Such minerals may exhibit some irregularity in the cleavage,but the amount of roughness is minimal.Poor cleavage occurs when the amount of rough surfaces dominate the amount of smooth surface area.Indistinct cleavage occurs when a mineral cleaves,but the smooth faces are so small that they are not noticeable.
如果你是在用英语学习医学,以上的说明应该已经足够你参考了,:-)
再问： 如果是在矿物学呢
再答： 如果是在矿物学，那Geology当中一般会在讲rocks and minerals的时候提到这两个概念。请看详细的定义区分：

Cleavage and fracture describe different ways in which a mineral can break.

Cleavage - The tendency of a mineral to break along flat planar surfaces as determined by the structure of its crystal lattice. These two-dimensional surfaces are known as cleavage planes and are caused by the alignment of weaker bonds between atoms in the crystal lattice. Cleavage planes are distinguished from fracture by being smooth and often having reflective surfaces.

Fracture - The way a mineral breaks other than along a cleavage plane.