Rock vs. Mineral

Difference Between Rock and Mineral

INTRODUCTION – There are many people who find it hard to answer when asked about the difference between a rock and a mineral, as they confuse both these to be one and the same. But there definitely lies a very subtle difference between the two, which sometimes, even the experts of geology, find difficult to explain.

DEFINITION – Rocks are composed of solid clusters made up of minerals and a few substances that are non- mineral in nature, such as glass, fossils etc. On the other hand, a mineral is a solid substance, formed naturally with the help of a number of geological factors, which has a characteristic and unique chemical composition and an atomic structure which is highly ordered. It may consist of elements and salts that are simple in nature or silicates. Any substance needs to fulfil certain requirements in order to be regarded as a mineral (e.g. Solid substance possessing a proper crystalline structure)

CLASSIFICATION – The classification of rocks can be done following two criteria viz. the texture of the rocks, as well as the composition (chemical or mineral) of the rock. On the basis of the texture, rocks maybe classified as Course grained rocks or Fine grained rocks, while they may be categorised into sedimentary, metamorphic and volcanic (igneous and plutonic), on the basis of their composition. Minerals, on the other hand, are classified on the basis of their chemical compositions only, and are put under different classes on the basis of the anions that are predominantly present in them. This is due to the fact that the chemical properties exhibited by the minerals resemble greatly, those exhibited by the anionic group that is so abundant in them.

Following the Rock Model Cycle, the rocks have a capability of transforming from one type to the other, when subjected to extreme external environmental, physical or chemical conditions. Volcanic rocks maybe forms when the magma from the volcanic eruption settles and cools down near the surface of the earth(igneous) or when it settles, cools and solidifies beneath the surface of the earth ( plutonic).

If we take the instance of sedimentary rocks are usually found to be near the surface of the earth and their existence is due to the continuous deposition and compaction of organic matter, silt and sediment.  Metamorphic rocks come into being as a result of transformation of other rocks, when they are subjected to different thermal as well as pressure conditions that are high enough to bring about a complete and drastic change in the nature of the original rock.

DIFFERENCE BETWEEN ROCK AND MINERAL – Irrespective of the fact that rocks and minerals are not that different from each other that they be placed two poles apart, they are two separate entities and the knowledge of the basic and the minute difference between them is a must for any student as well as person, who associates himself/herself with the field of Geology. The one aspect that differentiate rocks from minerals is their basic nature, because, while mineral, on one hand, is a naturally occurring substance having chemical composition that is well defined, a rock, on the other, is made up of an aggregate of many such naturally occurring minerals. Some rocks maybe homogeneous, that is, composed of a single type of mineral only, or heterogeneous, that is, made up of more than one types of minerals.  Some of the rocks may contain minerals eg. Quartz, that may be very common as regards their place of occurance, while some may contain minerals that are unique to a particular place. Certain rocks contain remarkably visible minerals, while others contain those that are only visible under high magnifications of microscopes

 

Thus we see that to be able to differentiate between a rock and a mineral is very important, because minerals are one hell of a valuable entities and any individual would hate to realise the fact that they passed on a valuable thing as a useless fact, just because of their inability to recognise it.