Diamond

Diamonds 

Diamond is a natural crystalline form of the chemical element carbon and is the only gemstone made up of a single element. The first Diamond was found in India about 800 B. C. The his country was a great producer of large size Diamond such as Kohinoor and

Diamond is a polymorph form of carbon.
The other form is graphite.
For carbon to turn into diamond

others.  The present total world production of natural diamond is about 100 million Carat to which India's contribution is only about 15,000 carats.  Australia as production figure of 1990 is world's largest producer followed by  Zaira,  Botswana USSR and South Africa.  Diamond occur most often as a euhedral or rounded octahedral and twinned octahedra known as Marcles.

 Crystal System

 Cubic

Crystal habit

Octahedral

 Fracture

 Sharp

 Cleavage

Perfect (IV set)

Lusture

Adamantine

Density

 3.5 to 3.53 gram per centimetre cube

Hardness

10

Specific Gravity

 3.47 to 3.56

 Melting temperature

700 degree centigrade

Reflection index

 2.41 to 2.43

 Types

Diamond proper:   well formed transparent

Bort :   Opaque or translucent

Bales :   spheroid aggregate

Carborando :   Fine grains and compact, dark grey to brown aggregate

 Made of Occurrence

1.  Primary Deposit
2.  Secondary (Placer) Deposit

 Primary Deposit

 Diamond is supposed to have form in gas saturated ultrabasic magma.  this Magma is   capable of dissolving to create quantity of carbon which is the source from which diamond   crystallise. when the Magma Delhi up to upper layer of the earth's crust cooled,  the 

 pressure of the gas is increased and a number of successive explosion took place at a   certain death. there are three views as to the place where Diamond are formed. They are:

•  The diamonds crystallized in situ,
•  The diamonds were originally contained in the underlined layers   of eclogite,
•  The diamonds crystallized in the original Magma chamber.

 Secondary (Placer) Deposits

 Depending on the mode of their formation the following genetic types of diamond bearing   places are generally, recognised :

• Alluvial,
• See-beach,
• Aeolian and
• Mixed origin

 Distribution

 Diamond deposit in India current Three Types of geological setting :

•  kimberlite pipes, 
•  Conglomerate beds and
•  Alluvial gravels

Conglomerate beds

 Panna belt
Upper vidhyan


Ramallakota-Banganapalli in kurnul district
Lover vidhyan

 kimberlite pipes

Wajrakarur in (A. P)  Anantapur district Panna belt (M.P.)

Gravels

 Panna belt, Krishna river basin Andhra Pradesh

Non -Material Material

 Petroleum and Natural Gas

Petroleum has been called liquid gold because of its value in our modern civilization. Petroleum is formed by hydrocarbons (a hydrocarbon is a compound made up of carbon and hydrogen) with the addition of certain other substances, primarily sulphur. Petroleum in its natural form when first collected is usually named crude oil, and can be clear, green or black and may be either thin like gasoline or thick like tar.

Origin 

 it is believed that the organic remains such as remains of plants and the animals organism, accumulated in the bottom muds  of lagoons  or in depression on the floor of Shallow sea and become incorporated in the accumulating sediments.  The bacterial actions that take place, decomposed the organic matter slowly into the mother material of oil by rem

oving Oxygen and nitrogen and giving rise to other changes.  The lower planktonic organism such as, diatoms and algae that thrive near the surface of the sea, are  considered the most probable and important source materials. In the other easy sense we can say that Millions of years ago, algae and plants lived in shallow seas. After dying and sinking to the seafloor, the organic material mixed with other sediments and was buried. Over millions of years under high pressure and high temperature, the remains of these organisms transformed into what we know today as fossil fuels.During Convection of the organic matter into Petroleum, natural gas which is dominantly method is also formed.
 The organic theory of all Genesis appeared for the first time in the form of   Lomonosov's distillation hypothesis, according  to which oil is considered to be a product of subsurface distillation of coal.

Geographical Distribution of Oil and Gas fields in India

 Andhra Pradesh

 Kaikalur, chintalapalli and mandepetta, Offshore area of Krishna and Godavari  (natural gas   field)
 Narsapur ancasa structure in the Offshore area of Krishna Godavari  (oil and gas field)

Arunachal Pradesh

 Ningru and Dum Duma  (oil and gas field)
 Assam
 Digboi, Moran, Dudrasagar,  changaigaon,  Lakwa and Sonari  (oil and gas field)
Adamtilla in Cachar district (gas field)

Gujarat 

 Ankleshwar, Kalol, Navgaon, Balal and dahej, Cambay basin (Nada), Kutch Offshore

Rajasthan

Jaiselmer basin

Tamil Nadu

Offshore areas of cauvery at  kovil-Kallapali and Nariman

 Bombay High 

Silicate mineral group

 The Silicate Group

The silicate mineral group is of the most important because they continue about 90% of the earth's crust, occurring as the major constituents of most igneous rocks and in appreciable quantities in sedimentary( except limestone) and metamorphic varieties as well.  most common silicate mineral are made up chiefly of a few of the following 9 element Na, K, Al, Mg, Fe, Li, Si and O. These include minerals such as quartz, feldspar, mica, amphibole, pyroxene, olivine, and a great variety of clay minerals.

 Every Silicate mineral contains Oxygen and Silicon. The basic unit in all silicate mineral is the Silicon-oxygen tetrahedron. The silica tetrahedron, a combination of four oxygen atoms and one silicon atom. These are arranged such that planes drawn through the oxygen atoms form a tetrahedron. Since the silicon ion has a charge of +4 and each of the four oxygen ions has a charge of –2, the silica tetrahedron has a net charge of –4.

Type	Similar names	Ratio	Examples
Nesosilicates	orthosilicates, independent tetrahedra or island silicates	Si:O = 2:7	olivevin Zircon gypsum kyanite
Cyclosilicates	Ring silicates	Si:O = 1:3	Beryl and tourmaline ( all hexagonal system)
Inosilicates	Chain silicates	Single chain Si:O = 1:3 Double chain Si:O = 4:11	single chain pyroxenes, Asbestos Double chain Enstalite, Amphiboles
Phyllosilicates	Sheet silicates	Si:O = 2:5	Mica, chromite and kaolinite (Al  is an imp.)
Tectosilicates	Framework silicates and network structure	Si:O = 1:2	Quartz feldspar and felspathoid