Diamond its properties, origin,mode of occurrence, varieties, distribution, uses.

1. DIAMOND
Sanjana Dhal
22GEOL028
M.Sc. 1st year

2. CONTENT
• Introduction
• Properties
• Origin
• Varieties
• Mode of occurrence
• Distribution
• Uses
• Conclusion

3. Introduction
• Diamond is a rare natural occurring mineral composed of entirely of
carbon.
• This is the only gemstone made up of single element.
• The first diamond was found in India about 800 B.C.
• Diamond’s atom are packed closer together than the atoms of any
other substance.
• Diamond has the highest melting point of any substance(3820 degree
kelvin).
• Diamond conducts heat better than any other substance .
• Diamond having the covalent bond.

4. GIANTCOVALENTBONDIN DIAMOND

5. Properties:
• Physical Properties:
• Crystal system-Cubic
• The crystals are mostly octahedral or dodecahedral
• Colour-white,blue,black,reddish,colourless
• Lusture- Admantine
• Cleavage-octahedral
• Fracture-conchoidal
• Specific gravity-3.5
• Hardness -10
• Diagnostic Property-4C (cut,Carat,Clarity&Colour).

6. Optical Beauty:
• Ability to reflect and refract light.
• Four factors
• Lusture-Quantity and quality of reflecting light.
• Brilliance-Amount of light returned to the eye from the diamond.
• Dispersion-Amount of rainbow colours returned to the eye from the
diamond.
• Scintillation-The sparkle when there is movement by a light source.

7. Origin:
• Most of the diamond found in the earth surface formed by magmatic
process.
• Some diamond are found in earth by placer deposit.
• Magmatic Process:
• For a ore deposit a source and Host rock are important
• In Diamond, source is lower mantle and host rock is kimberlite &
lamprophyre.
• Kimberlite-A potassic ultrabasic hybrid igneous rock.
• Lamprophyre- A ultrapotassic ultramafic hybrid igneous rock.

9. • The magma produced due to the partial melting of lower mantle
having low density than the surroundings so it will move towards the
earth surface.
• The magma coming from the lower mantle is enriched in CO2,H2O &
considered as high oxygen fugacity in comparison to upper mantle.
• While reaching the magma in the upper mantle ,due to reducing
environment of upper mantle the CO2 become pure (C) that is in the
form of diamond.
• After the formation of diamond the kimberlite brings the diamond
into the earth surface at a rising speed of 150km/hr.
• Kimberlite brings the diamond from a greater depth & lamprophyre
brings the diamond to the earth surface from shallow depth.

10. Varieties
• Diamond (proper)-Perfect crystal,transparent .
• Bort-Imperfectly crystallized diamond .
• Ballas-Spheroid aggregates with a radiated structure.
• Carbonado-Black diamond.

12. Mode of occurence
• Diamond primarily occurs in kimberlite pipe in disseminated manner.
• Age of diamond is older than the host rock i:e kimberlite &
lamprophyre.
• Diamond placer occur more frequently as eluvial placer & alluvial
placers.Ex.-panna
• Diamond also occurs in stratified conglomerate. Ex- Vindhyan
formation & in Kurnool formation.
• Diamond occur as pebbles in sandstone. Ex-panna(Madhya Pradesh).

13. Distribution
• North- Bundelkhand craton(lamprophyres reported)
• South- Dharwar craton (kimberlite reported)
• Eastern- Gondwana rocks
• Madhya Pradesh:
• Panna(Vindhyan ) shale
• Majhgawan pipe
• Jhiri shale(basal conglomerate )
• Andhra Pradesh:
• Cuddaph
• Anantapur-Wajrakarur diamond mine.
• Kurnool-Bangapalli group(conglomerate & sandstone)
• Krishna & Godavari.

15. Uses:
• Diamond is the most
valued Gemstone
• Diamond is used in
jewellry making.
• Used in industrial and
technical applications .
• Diamond bits are used
in drilling holes.

16. Kohinoor:
• The Kohinoor was mined from the Golconda region of Andhra
Pradesh .
• It is one of the largest cut diamond in the world ,original weight is 793
carat & its weight subsequently reduced over centuries & now its
about 105.6 carat(21.12g).
• The Kohinoor diamond was taken away by British east India company
& adorned the crown of Queen Victoria when she becomes the
Empress of India in the year 1877.
• Current owner of Kohinoor is Queen Elizabeth & a part of British
Monarch.
• It is the most expensive diamond in the world.
• Due to its uniqueness , the diamond is said to be Priceless.

19. Conclusion:
• Diamonds are one of the most unique minerals to be present on
earth.
• With their incredible hardness and unparalleled shine, diamonds have
made their way to not only the top of industries but top of consumer
markets.

20. Reference:
-A Text Book Of Geology By G.B. MAHAPATRA,CBS Publication.
-Economic Geology By Umeshwar Prasad,CBS Publication.
-Introduction to Ore Forming Processes By Laurence Robb.