In gems, some are known as Rock gemstones. We can say that rock can be used as gem because of its structural units such as minerals, elements, atoms etc. In this article you will obtain some informative facts about Rocks and their structural units. Hope, this article will not ruin your precious time and give you authentic information about Rock gemstones.
Different Types Of Rocks And Minerals
Rocks are made up of minerals or we can say that minerals are the basic structural units of Rock but few minerals are responsible for making rock so most of rock is made up from a combination of these rock forming minerals such as feldspars, mica, quartz, olivine, pyroxene, calcite and amphiboles. There are over 3000 different types of minerals but some of these are rarely present in quantities large enough to be considered rock forming. So to understand the Rock first of all you should know about its structural unit named as mineral.
What Are Minerals?
Minerals are made up of elements and these elements are simple substances that cannot be broken down into any other simple units or substance. The name of an element is written down as a combination of alphabet called a symbol e.g. sodium is Na and chlorine is Cl. And Salt is a combination of sodium and chlorine is thus written as a NaCl. Many minerals are made up of very large numbers of elements, so their formulas are complicated. The most common minerals are those based on silicon and oxygen and represented by formulae SiO4.
In this world, People from different countries search and value minerals for many different reasons. Most are beneficial as they are the metal’s raw material. The lead of the pencil is the graphite mineral mixed with clay. In commerce, precious metals are used and other minerals are considered as gemstones. Minerals are either found in special shapes which are called crystals or in the shapeless lumps which we called massive.
What is Crystal?
When atoms are arranged in specific geometrical patterns they form Crystals which are solid material. The crystal shape is the physical appearance of the regular internal atomic structure of the mineral. Their growth can be affected by temperature, chemical conditions; pressure and the amount of available space and some other things. Many of them are crystallize from watery solutions and some from molten rock as during volcanic eruptions.
Different range of crystal shapes determines each mineral formation. Although there are authentically thousands of minerals and their crystal shape can be determined on the basis of their symmetry/structure into seven systems of three dimensional patterns.
The color of mineral
The most striking and attractive feature of any mineral is its color. Due to color of any mineral we can easily differentiate the minerals. This important feature can varies from mineral to mineral and many minerals are a combination of different colors. What we see as color is basically a reaction between our eyes and brain. When daylight (white light) falls on a crystal, some of the wave lengths are absorbed and some are reflected back. Some of the waves of light are absorbed are those which make up the color that is not white. But some minerals for example rock crystal including the clear variety of quartz will receive light and reflect it back without changing it so they are colorless.
Idiochromatic Minerals
Other minerals are commonly always the same color because atoms which are responsible for absorbing certain light are an essential part of the atomic structure of the minerals as in Sulphur or Peridot (Olivine). These minerals are described as Idiochromatic.
Allochromatic minerals
Impurities in the crystal or defects in Light-absorbing atoms can produce minerals with a wide variety of colors. These give us yellow, red, green or blue variations of Beryl, Quartz, Diamond and Corundum etc. and Allochromatic Minerals is the term used for these minerals. One Allochromatic variation of Quartz mineral is known as CITRINE.