Rocks, Gems and Minerals
It is not a secret that gems are minerals that are formed from rocks and sediments. Each mineral group or a mineral itself has its own chemical composition made of the same ingredients or chemical elements. For these ingredients special chemical formulas identifying them exist.
Rocks are made up of one or more minerals. Those minerals that rocks consist of have their own identifying properties like crystal shape, hardness, reaction with hydrochloric acid and the color. Some of them are more useful than the others to identify the mineral (that depends on the mineral itself). The shape of a mineral crystal, colors of some minerals are useful for identifying the minerals. But there are cases when color is very misleading. A lot of minerals may have a set of different colors. For example, quartz comes in white, pink, purple, and gray colors.
Talking about gems I can say that they are minerals, sometimes rocks and petrified materials. All of them when cut or faceted and polished are collectible or can be used in jewelry. Besides mineral gems there are organic ones – amber, that is fossilized tree resin and a form of coal known as jet. Distinguish precious and semiprecious gems, and some of them are too soft or too fragile to be used in jewelry. But such stones are usually exhibited in museums and are sought by collectors.
The minerals is a global notion, a group which includes both rocks and gems. Minerals are elements or chemical compounds that are normally crystalline and that have been formed as a result of long term geological processes. The main difference between mineral rocks and mineral gems is their rarity and beauty. The rarer is the mineral (rock, gem) the more valuable it is. All of them have absolutely the same set of properties and value grading scales. One thing differs – gems are priced and compared more precise than rocks or other minerals.
Minerals are usually formed by inorganic processes, are crystalline solids, have specific chemical and physical characteristics. Minerals are commonly identified by the physical properties they possess. These physical properties include hardness, color, crystal shape, specific gravity (a measure of heaviness), and streak (the color of the mineral in the powdered form). Some other useful properties are different chemical reactions with acids. It is very easy to understand then, that few of the characteristics of the different types of rocks are the result of their mineral composition. Many minerals are valued by people because of the specific qualities or characteristics they display
Today we gave faced the problem of rocks, gems and minerals lack. Our civilization is now heavily dependent on geologic materials for constructing roads, buildings, bridges and monuments. Each year, the United States geological materials’ consumption reaches many tons per single person. This includes a great amount of stone that is not even considered a mineral. Stones that are used for building can be found in virtually any city or town, sometimes in a great many varieties.
