Ancient India and diamonds.- a brief note .

Navrang India January 03, 2015
Diamonds. independent.co.uk/

Diamonds have been around in India for more than 3000 years and there are references in the  ancient Indian mythological and religious texts as well as in the Greek and Roman classical  works of  the early 13th century. The great traveler Marco Polo and other early European explorers and traders  mentioned about the gemstones. Prominent traveler among the Europeans,  French man and the 17th century gemstone  merchant, Jean Baptiste Tavernier, made six visits to the the Indian subcontinent  between 1630 and 1668, and he  reported on some of the most famous large rough diamonds from this country. Prior to their discovery in Brazil in the early 1700s, India was the main world supplier of this important gemstone. The ancient diamonds were recovered from the alluvial deposits at the surface, or from shallow underground mining operations.
eruption brings the diamond-bearing rocka to the earth's surface shimansky.co.

Above image:  Formation of diamonds: They are formed deep in the eart roughly 150 to 200 km from the ground.  Molten kimberlite (also known as magma) within the Earth's upper mantle (below 150 km) under conditions of intense heat and pressure expands and rises at a rapid rate causing eruption on the surface. This gem is formed at high temperature of 1500 degree C and at pressure of around 5 Giga Pascal. Thus diamond-bearing  molten rocks reach the earth's surface.  This eruption must have happened long ago. The errupting magma forms a pipe connecting the earth's surface with the magma chamber.  
When  the magma cools, it hardens to form a rock called Kimberlite, the most significant source of diamonds. The Kimberlite settles in vertical structures known as Kimberlite pipes . These pipes are subject to other geologic processes  like weathering. stream erosion, etc. Ultimately, they are  transported from the source areas and deposited in the alluvial plains in many cases if  terrain in the sourse areas has rivers. ...........

Most of the world famous diamonds in the world  were of Indian origin and mined at Kollur  in the  Golconda  region (Goconda is part of  Hyderabad city,(Telengana, India). Believed to be a major diamond trading center way past, in Golconda town  there existed many small -scale industies  engaged in  cutting and  polishing not only of diamonds but also of  other precious stones such as rubies, Sapphire,  emeralds, Beryls, pink garnets, emeralds, etc. The Golconda - region  covered  vast placer deposits along the rivers of  Krishna-Venva  between the lower reaches of the Godavari, Wainganga, Wardha and Krishna. Now, these places come under part  Maharashtra and Andhra Pradesh states

Until  the early eighteenth century India had been a regular  supplier of diamonds when diamonds were discovered in  other countries like south Africa/Brazil. By this time diamond mining in India had already begun to decline and later became dormant.  There were many areas where diamonds were mined, but  the verifiable historical records are fewer in number  and  many of them were lost in antiquity. In southern India,  diamond activities were confined to present day Telengana and Andhra states. The source rocks in many places in the world  are Kimberlite and  Lamproite rocks and the  are found in parts of Andhra and Karnataka on a low scale. The Indian Geological Survey ihas been unsuccessful so far in locating diamond deposits that will be commercially operational. .

Kingdom of Golkonda, India. harada.ho-seki.com
Briolette diamond, oldest diamond, India www.etoolsage.com
Arthasastra  written by Kautilya (Chanakya) in  the late fourth century BC was probably the first text to describe the Indian diamond or ''vajra''(Sanskrit for "adamantine")  and its mode  and areas of its occurrence (2.11. 37-41). Diamonds were discovered in in  the 4th century B.C. The speciality about Indian diamonds is they  were known  for their size. beauty, purity, lustre reflections, etc but the  very high quality of diamond was available in small  quanity. The sources were   the  placer deposits. of the so-called "lost mines of Golconda" (Kollur).   
Bearman Cartoons

Formation of diamond-jewelry-pedia.com

diamond formation jewelry-pedia.com

Diamond formation in the earth. nkaiserscience.wordpress.com
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Punch - PhotoShelter
It is hard to identify precise locations of those names mentioned in Arthasastra, Brhat-samhita, Ratnapariksa, Agastimata, or other texts describing gems, precious stones and  diamond fields, but we may guess the following locations: Wairagadh eighty miles south-east of Nagpur on the Bath river, a tributary of Weinganga ; the Kosala region of Akaravanti around the famous Panna in Madhya Pradesh; the region around the Golkonda mines, formerly known as Matanga; the Paunda or the Chota-Nagpur area around Soumelpur; the Kalinga alluvial resources from the Mahanadi valley, the Sambalpur district, the Koel river Hirakund, etc.
The main diamond occurrences in India fall into three  areas:

01. The “Southern group”  comprising the states of Andhra Pradesh and Karnataka, including the historical Golconda region and the most famous of the three producing areas, with the deposits associated with the Dharwar Craton. The mines are located in the Mahbubnagar, Bellary, Karnul, Guntur, Kristna and Godavari districts.

02. The “Eastern group” mainly in the state of Orissa in the Aravalli Craton. The mines are located in the Raipur and Sambalpur districts.

03. The “Northern Group” :This includs  the states of Madhya Pradesh and Maharashtra in the Bastar Craton. The mines are located in the Panna district. Among them, Panna area yielded diamonds in the recent past, but presently, there are no mining  activities. 

The following text-books or publications will be of some interest: 
 .  
 a. Early Records of Diamond Mining in India, Fareeduddin, R.H. Sawakar, 10th International Kimberlite Conference, Extended Abstract, pp. 1-4, (2011): The authors say while diamonds had been known for more three thousand years, exploitation of the diamond deposits reached its peak  in the 17th century and then, following their discovery in Brazil, production in India dwindled sharply. 

b.“Classic Mineral Localities of the World – Asia and Australia”, P.Scalisi, D. Cook, Van Nostrand Reinhold, New York, pp. 53-64, (1983). This book contains a section on the historical Indian diamond mines, and it gives a brief description of the famous diamonds from this country.

c. Evolution of the Indian Diamond Industry, J. Panjikar, K.T. Ramchandran, Indian Gemmologist, Vol. 13, No. 1/2, pp. 27-38, (2005). The authors review the history of diamonds in India, and they discuss the ancient diamond mines in particular parts of the country.

d. Diamonds from India to Rome and Beyond, L. Gorelick, A.J. Gwinnett, American Journal of Archaeology, Vol. 92, No. 4, pp. 547-552, (1988).  It is quite interesting the authors point out that  the technological use of diamonds as tools, for example as splinters for engraving gems or drilling holes in beads, appears to have begun in India at least as early as 250 BC.
(Above references  are from: https://www.gia.edu/diamonds-ancient-india-reading-list (by Dr. James Shigley)

Ref:
https://www.quora.com/How-did-the-ancient-Indian-Kings-get-gold-and-diamonds
Biswas, Arun Kumar. 2001. Minerals and Metals in Pre-Modern India. New Delhi: D.K Printworld (P) Ltd.
https://www.diamond-jewelry-pedia.com/diamond-coming-to-earths-surface.html#.Xus7QmgzaM8
www.allaboutgemstones.com,