Since the early Iron Age, 3,300 years ago, people develop new and new ways to use minerals mined from the earth’s crust. Modern industry is still dependent on the mineral resources of the earth. Scientists there are about 3,000 species of minerals, but only 100 of them are fairly common. Minerals are inorganic (inanimate) world. Most often, they are solids. The exception is the mercury.

The list of top 10 valued minerals in geology looks like this:

1. Diamond
2. Emerald
3. Ruby
4. Sapphire
5. Amethyst
6. Beryl
7. Topaz
8. Quartz
9. Citrine
10. Ametrine

Many minerals have specific properties which are easy to learn. For example, native element arsenic smell like garlic when heated, and talc – soapy to touch. Some minerals fluoresce (glow or change color) in the ultraviolet or X-rays. Other electrically charged when heated or under pressure. And there are minerals, which can be recognized only by means of special tests in the laboratory. Some dissolve only in hot acid, and not in the cold, other – only concentrated, but not dissolved.

Minerals have a definite structure and its chemical formula. The chemical formula of halite (rock salt) NaCl. This means that the halite – a chemical compound of sodium (Na) and chlorine (Cl).

Since each of the mineral composition of a definite and permanent, the atoms of its elements are building the correct three-dimensional lattice structure is specific to it. These lattices are geometric shapes, flat faces which are arranged symmetrically. If you for some time to leave a flat dish a little salt water, it evaporates, and at the bottom of the salt crystals are formed. In the magnifying glass it is revealed that these are correct cubes.

There are seven main crystallographic, or isometric, systems, called symmetry. Diamond, for example, belongs to the cubic system, Ruby – hexagonal, turquoise – to triclinic. Each system can be described according to the specifics of its symmetry – the property that when the crystal is rotated about an axis allowing it to appear in the identity as two or more times for one complete revolution. The crystal can be determined by the number of axes of symmetry.

Precious minerals

Back in the Stone Age people did gold jewelry, in the Bronze Age – from silver. Today, we have discovered many jewelry available minerals. The most expensive gems among top 10 valued minerals in geology are: diamond (especially white), as well as emerald, ruby ​​and sapphire, are valued primarily for color. These stones are so expensive that their weight is measured in carats. One carat equals 200 milligrams.

Diamonds are formed under extreme pressure in the structures of igneous rocks in the form of pipes, kimberlitic substances. They originate deep in the Earth’s mantle. Diamond is a kind of pure coal and chemical composition is different from an ordinary soft mineral graphite pencil familiar to us. Diamond valued for hardness and shine, acquired in cutting and polishing. The reason for this difference between diamond and graphite is that they have a different internal structure. Ability of a substance to exist in two or more forms with the same chemical composition is called polymorphism.

Top 10 valued minerals in geology usually belong to some general type of minerals, which are found more often.

For example,

• The emerald is a rare type of beryl
• The most beautiful specimens are found in Colombia (South America)
• And the most famous rubies in the world (a type of solid mineral corundum) – Myanmar (formerly Burma)
• Beautiful sapphire (blue corundum) is mined in Sri Lanka and Thailand

The aim of petroleum geologists is to find traps or accumulations of petroleum. The trap not only must be defined but must exist where other conditions such as source and reservoir rocks occur.

To locate these traps, the geologist must rely on subsurface information and data gathered by drilling exploratory wells and data obtained by geophysical surveying. These data, once interpreted, are used to construct maps, cross sections, and models that are used to infer or to actually depict subsurface configurations that might contain petroleum. Such depictions are prospects for drilling.

Petroleum Engineering

Greater efforts in petroleum geology along with petroleum engineering are being made to increase recovery from existing fields. Of all oil discovered so far, it is estimated that there will be recovery of only 35% on the average. Recovering some part of this huge oil resource will require geological reconstruction of reservoirs, a kind of very detailed and small-scale exploration.

These reconstructions and models have allowed additional recovery of oil that is naturally movable in the reservoir. If the remaining oil is immobile because it is too viscous or because it is locked in very small pores or is held by capillary forces, techniques must be used by the petroleum geologist and the petroleum engineer to render the oil movable.