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