Cleavage vs Fracture
The words cleavage and fracture are very common words that are used in many contexts. However, it is while identifying minerals that these words are used together as these are physical attributes of minerals and help in mineral identification as different minerals have different types of fractures and cleavages. Like color, density, luster etc, fracture and cleavage become a basis of differentiation between different minerals. There are some who remain confused between cleavage and fracture, though there are differences that can be easily understood. Read on to know all about differences between cleavage and fracture.
To begin with, both cleavage and fracture are physical characteristics that tell all about how a mineral gives way under pressure, or in other word, how it breaks when stressed. If the crystal or mineral breaks under pressure in such a way that the broken piece has a smooth surface, it is said to have cleavage. However, if there is never a smooth plane when the crystal breaks, it is said to have no cleavage. However, cleavage can be of many qualities such as perfect, good, poor, indiscernible etc., and this is how minerals get categorized according to their quality of cleavage. Then, there are differences in number of sides exhibiting cleavage as there are minerals only showing cleavage from one side, while there are some that exhibit cleavages on all sides.
Fracture, on the other hand is the mark left on a crystal when it breaks when the atomic bonding between atoms in its crystalline structure shows no weakness and is perfect. Such minerals, when put under stress, break into pieces, no two of which are alike. Fracture is basically either conchoidal or non conchoidal. The way glass breaks is an example of conchoidal fracture where one see circular patterns in broken pieces, whereas when quarts break, pieces show non conchoidal fracture with no fixed pattern.
But the moot question is, whether you need to break a mineral to know about its fracture or cleavage characteristics. No, certainly not, as it is possible to know about these properties analyzing areas of stress where the mineral could break or chip, if pressure is increased. It is a fact that minerals with little or no cleavage, fracture more than those with perfect or good cleavage.
What is the difference between Cleavage and Fracture?
· Cleavage and fracture are physical characteristics that help in identification of a mineral.
· Cleavage is the manner in which a mineral breaks along its plane of weakness. These are the planes where atomic bonding in crystalline structure is weak and gives way when the mineral is put under stress.
· Fracture is breakage of mineral when atomic bonding is perfect and there is no weakness.
· Minerals with poor or no cleavage fracture more than minerals with perfect cleavage.