Thursday, September 24, 2009

Evolution of the Indian Diamond Industry


ABSTRACT
The famous legendary diamonds are spread out in all corners of the globe -the “Kohinoor” diamond is in the British Crown Jewels in England, the blue coloured “Hope” diamond is in the Smithsonian Institute Museum in the United States of America, the “Regent” and the “Sancy” are in the Apollo Galerie of Louvre Museum in France, the “Orloff” is in Russia, the “Dresden Green” is in Germany, the “Darya-i-noor” is in Persia, the “Florentine” is in Austria, All these famous diamonds came from the old Indian mines.
Indian diamond industry started more than 3500 years ago. Mythological and religious idols dating back thousands of years are shown bedecked with diamond jewellery. Diamond is known in the Sanskrit language as “Vajra”. Four thousand year old, Vedic literature gives accurate detailed description of a “Vajra” as a perfect octahedron.
It would be of great gemmological significance to know from which mines the famous diamonds came. Their diverse colours, their large awesome sizes and the fact they were found in large quantities, makes it an interesting study. The ancient Indian diamond mines were situated in three main groups, Southern, Northern and Eastern groups.
At one time it is said, this diamond-bearing region of the southern group known in the olden days, as “Rayalseema”, was flooded with diamonds of big sizes. Reliable evidence is available of a flourishing diamond trade and industry in this region. Later, when the British ruled India, many of these mines were under the Golconda Diamond Mining Co, a British company with its Head Office in Madras. Hence most of the diamonds were said to come from Golconda. Geographically this diamond-bearing region lies in a large area between 13°20’N latitude to 17°0’N latitude and 77°47’E longitude to 85°15’E longitude which comprises about 336 km (210 miles) long and 152 km (95 miles) wide.
This paper intends to the trace the evolution of the diamond industry dating from 4th Century B.C. to the present day. Detailed descriptions of some 23 diamond-bearing mines along with maps are provided.
INTRODUCTION
Alluvial diamonds were known in India as early as 800BC (Bruton, 1978). The diamonds were found in compact sandstones and conglomerates and in the sands and gravels of river - beds and terraces. Indian diamonds were exported through the port of Alexandria at an early time (Maillard, 1980).
The ancient Indian diamond mines were situated in three main groups. (Fig. 1)
Indian Diamond Mines are grouped as

1. Southern Group
These ancient mines of the southern group were the most famous and contributed to the legendary diamonds. The mines were stretched across the vast land from the Godavari River near Hyderabad to the Pennar River in the south, as well as the entire span of the Krishna River belt. It comprises a vast area, which includes parts of Anantapur, Cuddapah, Kurnool, Guntur, Krishna and West Godavari (Babu,1998). This area usually referred to as Golconda, was one of the five mediaeval states formed after the disintegration of the Kingdom of Deccan. Golconda existed as a State from AD 1347 to 1687 and the city of Golconda was the capital. Golconda was not a mining area but was a very important mart for the diamonds, which were mined in the state as well in the adjacent states. Vajrakarur (vajra= diamond karu=lake vajrakarur means diamond lake) and Lattavaram are the kimberlite diatremes being worked even today(Mukherjee,2002).
2. Northern Group
In the Bundelkhand district of the then Central Provinces, between the rivers Ken and Son lie the northern group of workings. There are three types of deposits a) alluvial terraces, b) conglomerate rocks and c) volcanic pipe situated at Majhgawan which lies 12 miles south west of Panna. The Panna Diamond Mines as they are popularly known, have been recorded in the 16th century AD. In the earlier days, most of the shallow gravels especially the alluvial and lateritic as well as the exposed conglomerates were worked on (Chatterjee & Rao,1992).
In 1827 Capt Franklin discovered the Majhgawan pipe, which was termed as kimberlite pipe much later by Sinor in the 20th century. Besides Majhgawan there are two other kimberlite diatremes known as Hinota and Angore, which are not very productive.
3. Eastern Group
The eastern group spreads from Chhotanagpur plateau in the basins of rivers (Sankh and Koel which come together to become river Brahmani) in the Ranchi District (23° 16': 84° 17') and in Palamau (23°35': 84°21') where occasionally large diamonds especially blue coloured diamonds have been found. It is said the area near the Hirakud Dam (Hirakund Hira=diamond, kund= basin), Bondisar in Kalahandi district, various places in the Boudh districts have yielded diamonds. After the monsoon season, especially after the intense flooding of the regions, large- sized diamonds were found in the gravel deposits. Most of this region has Pre-Cambrian rocks and terefore besides diamonds other gemstones have also been found here (Babu, 1998).
The eastern group further continues in the Mahanadi river valley in the neighbourhood of Sambalpur district of Orissa as well as in the Raipur district of the newly formed Chhatisgarh State. Here recently four kimberlite pipes have been discovered (Small & Vaidya, 2002).
Tracing Back History
4th Century BC
Chandragupta Maurya ruled a major part of India in 4th century BC and was known in the Greek language as “Sandrokottos”, as described by the Greek traveller, Megasthenes. Kautilya was the minister of the king Chandragupta. He wrote a Sanskrit manuscript “Artha Sastra” – translated as “Lessons of profit”. In this treatise, Arthasastra, Kautilya has given details of the diamond occurrences, trade and valuation (Lenzen,1983). Not only did the ancient Indians have knowledge of diamonds in the 4th century BC, but they also used diamonds as commodities of active trade. Diamonds were subject to taxation and were one of the sources of royal revenue. Value of diamond was recognized and there were manuals for judging the value like – “Ratna Sastra” meaning Gemstone-Science and “Ratna Pariksha” meaning Gem-testing and evaluation. The descendant of King Chandragupta was the Emperor Ashoka, who had a huge empire that had the majority of the diamond mines.
Rock Edicts of Ashoka (or Asoka)
During the times of Emperor Ashoka in 245 BC, lithographs were made in Pali language. Inscription on rocks were called “Shila Lekh” and those on copper plate were called “Tamrapatra”. In a place called Jongiri, these rock edicts still exist in Pali script. There are some 5 large rocks with clear inscriptions preserved on them, stating that the diamonds, gemstones and gold are found here and all that is found belongs to the Emperor Ashoka.
After Emperor Ashoka many dynasties ruled this region; to name a few Chalukyas, Vijaynagar, Bijapur, Nizam, the British and now it is part of the state of Andhra Pradesh in the Union of India.
The early literature gives an elaborate knowledge of diamonds. Pliny (1st century AD), Ptolemy (2nd century AD) and Buddhabhatta (5th century AD) have reported elaborately about diamonds from India. In the 6th Century AD, the writer of the “Brahat Samhita” written in Sanskrit, makes accurate references to some eight diamond-occurrences especially to Matanga or Telangana region, which includes the Krishna and the Golconda districts. In the 10th Century Garud Mahapuranam gives similar occurrences for diamonds (Satyanarayan, 2002).
Vajra Bhandar
During the days of the Vijayanagar Kingdom, Maharaja Achutrai ruled the region. A lithograph written in Telegu and Kanada script of that time is located at Annupally. It states that in the year 1336 there was mining of diamonds in this area called Vajra Bhandar. When diamonds were found, they were washed in the large pond at Annupally and then sent to the capital. In that period there existed a very large diamond market with huge cubicles made of rock. These stone structures are still to be seen today at Hampi. They bear witness and give evidence of great commercial activity. It is said that envoys of all major kings and emperors from all parts of the world came here to deal. There were facilities for lodging, boarding and entertainment for all, envoys, merchants and dealers.
Foreign Travelers
In the 13th Century Marco Polo travelled to India and in his travelogue he refers to this diamond district. Later Niccolo de Conti, an Italian trader in the 15th Century, made several voyages to India. He has given a very vivid description of the diamond mining as well as of the annual animal sacrifices offered to the temple Goddess before mining was carried out. The meat of the animals was thrown into the valley infested with wild animals. Many a times the vultures lifted the pieces of meat to which diamonds were stuck. These diamonds were later retrieved from the nests. He also describes the “valley of diamonds”. This may be of interest to the western world as there are several paintings and descriptions of the same in various museums (Maillard, 1980).
In 16th century Domingo Paes and Fernao Nuniz travelled to India and they have described the wealth of Hindu King of Vijaynagar as well as the mining of diamonds. Diamond mines were worked on a royalty system. One of the strictest conditions was that all stones above 10 carats were to be sent to the “Raja” or the king for his personal use (Satyanarayan, 2002).
Then in the 17th century, Monsieur Tavernier, a jeweler by trade, who really knew the importance of diamonds made six voyages to India, between 1636 and 1662, for the purpose of collecting gems. He actually visited many of the mines and stayed at a big Serai near the village of Karwan on the main road to Golconda, where diamond cutters and polishers lived (Maillard, 1980).
SOUTHERN GROUP
“Rayalseema”
In the olden days the entire diamond-bearing region of the southern group, known as “Rayalseema”, was flooded with diamonds of big sizes. Reliable evidence is available of a flourishing diamond trade and industry in this region. In 1928, Leonard Munn, Mining Engineer, Special Officer to the Geological Survey Department, wrote “A History of the Golconda Diamond Mines” in which he gave various details about the geology and the locations of the mines.
Geology
A series of Pre-Cambrian rocks occur in Southern India as Karnul formations. They are probably of the same date as the other Vindhyan Series occurring in the middle and southern India. Anil Kumar & Gopalan, 1992 estimate the Rb/Sr age to be 1091Ma of the Vajra Karur Kimberlites.
The Geological sequence of the rocks in Banaganpilly. And lowest of all another set of quartzites (sandstones, pebbles etc.) are rocks of the Banaganpilly Group. is given below
The Khoodair Group ----------- [ Nundial Shales
Koilkoontla Limestones
Under these a series of quartzites
The Paneum Group ------------ [ Pinnacled Quartzites
Plateau Quartzites
Beneath these comes another series of shales and limestones with local intercalations of silicious beds.
The Jummulmudgoo ---------- [ Owk Shales


Nerjee Limestone
It is in the lowest strata known as the Banaganpilly sandstones that the diamonds have been found. The thickness of these rocks varies between 4 to 5 feet. The dip of the beds is nearly horizontal.
The Banaganpilly Group consists of sandstone-and-grit-quartzites, with bands of pebble beds and some conglomerates. The sandstones are generally coarse, often with a clayey constitution, occasionally felspathic, or ferruginous and usually of dark shades or red, grey and brown colours. Pebble beds are rather more characteristic of this group and are composed of quartzite and various coloured cherts, jaspers and hardened shales. The diamonds occur in some of the more pebbly and clayey layers.
Golconda Diamond Mines
In the year 1677, the Right Honourable Earl Marshall of England, Henry Howard, published an important paper on the Golconda Diamond Mines, in the Philosophical Transactions of the Royal Society Of England. In his paper he mentioned that India was the sole source of the world’s supply of diamonds. There was ample and reliable evidence that “the richness of these mines was enormous and their wealth became proverbial”.
This important paper gave the first detailed description of 23 Mines in the Golconda region. The name “Golconda” was affixed to the mines, although they lay very far south of the Golconda Fort, because it was the name of the capital, the treasury and the mart for diamonds. Later, when the British ruled India, many of these mines were under the Golconda Diamond Mining Co, a British company with its Head Office in Madras; hence most of the diamonds were said to come from Golconda.
Golconda mines, geographically lie in a large area between 13°20’N latitude to 17°0’N latitude and 77°47’E longitude to 85°15’E longitude which comprises about 336 km (210 miles) long and 152 km (95 miles) wide. This area now forms the parts of the Cuddapah, Kurnool, Bellary, Krishna and Godavari districts.
Between the 16th and mid 19th centuries there were nearly thirty open pit mines in operation in Golconda. Prime amongst them was Kollur located 80km from the Bay of Bengal. Other well-known mines were Partial, Gollapally, Ramallakota, Mallavally and Banganapally. Some of these mines were tunnels some were pits and others deep pits. The pits were only a few feet deep and the soil that was dug up was sent up in open trays a relay of workers standing along never-ending lines. In the mines the diamondiferous layer was observed as a seam of about six or eight inches thick, between thicker and harder beds of sandstone. The layer occurred as a very fissile damp clayey conglomerate and breccia, of small rounded fragments and pebbles of varied coloured shales and quartzite. The gangue was then pounded up, washed, shifted and laid out to dry on prepared floors after which the residue of clean sand was carefully examined manually by the women and children. These workers dug with remarkable precision and when large sized diamonds were unearthed they were washed, dried and then examined in the bright sunlight. There were 30,000 to 60,000 workers in every mine and the entire working was an organized operation. Any diamond above l0 carats was the property of the king (IDEX magazine 2003).
Locations of the mines, where some of the famous legendary diamonds were found, are given below :
MAHBUBNAGAR DISTRICT
There are three famous mines in the Mahbubnagar district
Somsila l6°03’N: 78°20E
Amaragiri 16°04’N: 78°23’E DARYA-I-NUR Diamond and NASSAK Diamond were found here.
Bollaram 16°5’N: 78°26’E.
BELLARY DISTRICT
In this district the three famous mines are :
Gunjeegoonta, 2 miles South of Wajra Karur, Lat. 15°77’N: Long. 77°42’E
Vajra Karur, Lat. 15°2’N: Long. 77°27’E Here the FLORENTINE and the BAZU diamonds were found.
Lattavaram 14°56’N: 77°47’E.
KARNUL DISTRICT
More than twenty diamond mines were operational in this district at one time. The famous among them are :
Banganpilly : Lat. 15°18’N: Long. 78°16’E SHAH DIAMOND was located here
Baswapur, Lat. 15°25’N: Long. 78°43’E.
Byanpalle; Lat. 15°32’N: Long. 78°14' E; 24 miles SSE of Karnul.
Polur: Lat. 15°31’N: Long. 78°19’E Diamonds were found on the banks of Kundur river; in Nandikotkur Taluk. HOPE diamond was found here
Kannamadaklu : Lat. 15°42’N: Long. 78°14’E POLAR STAR was found here.
Lanjapoleur : Lat. 15°45'N30"; Long. 78°4' 7 miles SSW of Karnul; Rammalakota Taluk. TAJ-E-MAH diamond was found here.
Muddavaram: Lat. 15°29’N: Long.78°30’E 7 miles ESE of Rammalakota ; Nandial Taluk. SANCY diamond was found here.
Munimadagu : Lat. 15°15’N: Long. 78°2' E in Pattikonda Taluk.
Rammalakota : Lat. 15° 34'N: Long. 78 °3' E 18 miles W. by S. of Karnul KOHINOOR Diamond was found here.
GUNTUR, KISTNA AND GODAVARI DISTRICTS
For centuries, diamonds were found in these places, among them the known localities were as follows: Atkur; or Atanur : Lat. 16°38’N: Long. 80°23’E IDOL’EYE diamond was found here
Bollupadu: Lat. 16°38'N: Long. 80°23’E
Golapalle (or Golapilly): Lat. 16°43'N: Long. 80°57’E
Kodavatakullu Lat. 16°40’N: Long. 80°23’E
Kollur (the Gani or Coulour of Tavernier): Lat. 16° 42’N: Long. 80°12’E; right bank of Kistna. The ORLOFF Diamond was found here.
Moonaloor (or Moogaloor) : Lat. 16°38'N: Long. 80°23’E.
Ustapalle: Lat. 16°40’N: Long. 80°23’E
Partial: Lat. 16°39’N: Long. 80°27’E REGENT diamond was found here.


NORTHERN GROUP
The Northern Group of workings lie between the rivers Ken and Sone. The ancient workings were mostly alluvial gravels and exposed conglomerates. The most famous area was the Panna Diamond mines and it was under the Mughal rule. The famous diamonds AKBAR, SHAH OF PERSIA, AGRA and SWAN were found here.
In Panna area, records of diamond mining goes back to the 16th century A.D. Most of the shallow gravels (alluvial and lateritic) as well as the exposed conglomerates were worked. In 1956, the Geological Survey of India (GSI) and the Indian Bureau of Mines (IBM) undertook surface sampling in the kimberlite pipe. 14 pits on 75m square grids were dug to establish surface dimension of the pipe and diamond incidence, six of which were subsequently deepened by National Mineral Development Corporation Limited (NMDC).
Till 1959, diamond mining was under a private party viz.M/s. Panna Diamond Mining Syndicate. Presently studies are being carried out to increase the production that will require mining and processing of about one million tones of tuff.
Geology
The only regular diamond producing mine in the country is the Majhgawan pipe in Panna district, Madhya Pradesh and located 15km WSW of Panna town. The pipe occurs in an ideal geologic and tectonic setting favourable for emplacement of alkaline ultrabasic diatremes. The pipe is intrusive into intracratonic basin of platform sediments of the Vindhyan Supergroup of Upper Proterozoic age. Immediately to the north lies the Bundelkhand craton of Archaean basement which is composed primarily of granites and granite gneisses with small enclaves of older metamorphics and basic and ultrabasic intrusive. The basement rock is overlain by the rocks of the Vindhyan Supergroup, which consist mainly of sandstone, shale and limestone etc. (Mathur, 1981).
The generalized geological sequence in Panna area is given below
Rewa Group
Ultrabasic
diatreme Sandstone,
Shale
Conglomerates
Kimberlites/
lamproites
Upper
Proterozonic Vindhyan Super Group Kaimur Group Baghain Sandstone
Pipartola
Conglomerate
Semir Group Palkawan Shale
Pandwatall
Sandstone Archaean Bundelkhand Granite and
Granite gneiss
Geomorphologically the Vindhyan sediments in Panna area are characterized by two plateaus with sharp escarpments (a) the lower Panna or Baghain Plateau which is a remarkably horizontal rising to about 300 m above the Archaean basement and (b) the upper Rewa plateau to the south. Both the plateaus with their escarpments trending ENE-WSW run parallel to the trend of the Vindhyan sediments as well as the well-marked ENE-WSW lineaments. The ultrabasic pipes at Majhgawan and Hinota are located in the Panna plateau and intrusive into the Baghain sandstone of the Kaimur Group. The sandstone has a gentle 2-5 monoclinal dip towards southeast.
Kimberlitic and Lamproitic nature of Majghawan
The Majhgawan pipe occurs on the western limit of the Panna diamond belt (80x85km) and is emplaced along a well-marked ENE-WSW lineament. Study of satellite imagery clearly brought out another set of lineaments (trending NNW-SSE), traversing the belt. The Majhgawan pipe is ideally located at the intersection of the above two perpendicular sets of fractures/lineaments (Chatterjee and Rao, 1992). The Hinota pipe lying at about 3.5 km northwest of the Majhgawan pipe occurs along the NNW-SSE lineament. According to Janse (1992), the Majhgawan mine was developed on a lamproite, which is located on the margin of the Aravalli archon.
According to Chatterjee & Rao, 1992, the alkaline ultra basic diatreme at Majhgawan has an idealized geological setting being intruded into platformal Kaimur sandstones of the Lower Vindhyan Supergroup (1400-1100Ma). The overlying cratonic Bundelkhand Granite Basement (2550 Ma) is a typical archon as per Janse (1992). Recent Rb/Sr age data indicate the age to be between 1042 Ma (Smith 1992) and 1097 Ma (Anil Kumar and Gopalan 1992), for the Majhgawan pipe. The pipe is a carrot shaped body reminiscent of a typical kimberlite with minimal erosion. Scott-Smith (1989, 1992a) has classified the rock as a lamproite. He has termed it as Olivine lamproitic lapilli tuff of crater facies. High TiO2 (4.6%), less abundance of typical heavy indicator minerals (HIM) like group 10 pyrope garnet and ilmenite and overall petrological characters of the pipe strongly reflect lamproite nature. High amounts of certain minor elements such as Ba (3000 ppm), Sr (1000 ppm) and REE (high La, U/Th ratio) also indicate its lamproitic character.
On the other hand the typical carrot shape of the plug, almost concentric distribution of diamonds, mode of presence of mantle derived xenocrysts, overall chemistry with high MgO (25%) low K2O (1%) and fair amounts of Cr and Ni are highly characteristic of Kimberlitic nature. Broad petrographic characters coupled with abundance of xenocrysts and occurrences of country rock xenoliths and geochemical characteristics suggest it is in several aspects typical kimberlite rather than lamproite. The garnet population with fair amount of harzburgitic pyrope and larger share of Iherzolitic variety indicate characteristics almost intermediate between kimberlite and lamprorite.
According to Ghosh & Soni 2002, by virtue of their geochemistry and petro-mineralogical character, the Majhgawan pipe rocks are uniquely placed among diamondiferous rocks of the world. Earlier the Majhgawan diatreme was referred to as a kimberlite pipe on the basis of geochemistry and mineralogical assemblages. Detailed mineralogical study of Majhgawan pipe indicated presence of pseudomorphs of olivine, chrome-diopside, amphiboles (hornblende, actinolite, tremolite), magnetite, limonite, chlorite and garnets. Spinel, calcite, zircon, perovskite, barites, and diamonds are also recorded. Possible melilite, rutile, titanomagnetite, pectolite, dolomite have also been recorded. On the basis of magnonian ilmenite, talc and vermiculite, chlorite and calcite and on the basis the other evidences this rock has been named as lamproite. Further, on the basis of the absence of the typomorphic monticellite (primary), abundance of pholgopite cognate, frequent presence of barite and primary calcite and other chemical characters, the Majhgawan diatreme has further been named as orangeite.
Comparison of inclusions in Vajrakarur (Southern Group) and Majhgawan (Northern Group)
Diamonds contain inclusions of other minerals (Mukharjee, 2002) from which the genetic relationship between diamond and the minerals can be assessed.
According to Mukherjee 2002, spinels are found as inclusions in diamond and such inclusions have generally distinctive chemical compositions. These are considered to be cogenetic with diamond host. Spinels of related composition can be readily used in differentiating between mineralized and non-mineralized source rocks. These indicator minerals are normally more abundant than the diamonds in a pipe and give valuable information for planning exploration.
Vajrakarur (Southern group)
Vajrakarur pipe-10 is situated near Anumpalle village, 17km east of Vajrakarur at the intersection of two lineaments trending N30W and ENE and has intruded into granitic terrain. Anumpalle kimberlite shows macrocrystic olivines, which are serpentinised olivine, and have other constituents like phlogopite and limonite.
Majhgawan (Northern Group)
The Majhgawan pipe in Madhya Pradesh occurs on the western limit of the Panna diamond belt and is emplaced at the intersection of two sets of lineaments i.e. ENE-WSW and NW-SSE. The pipe is intruded into the Baghain sandstone of the Kaimpur Group of Proterzoic age (1100Ma) and varies considerably in lithology.

Mineralogically the principal phenocrysts are spinel, perovskite, pyrope, ilmenite and phlogopite. The groundmass predominantly consists of serpentinised olivine, phlogopite and ilmenite.
According to Mukherjee 2002, the diamond inclusions can be allocated into two suites i.e. peridotitic and eclogitc. Spinels from kimberlites show limited ranges in Cr2O3 (42-63%)[Cr/(Cr+Al)] ranges from 0.7-0.95 in diamondiferous kimberlites. The Fe/Fe+Mg and Cr/Cr+Al ratio percentage of spinels from Vajrakarur pipe-10 range between 0.26 to 0.51 and 0.33 to 0.72 respectively and spinels have compositional character of spinels occurring as diamond inclusions from world-wide diamond localities. Spinels from Vajrakarur were classified based upon the predominance of Cr2O3, A12O3, TiO and MgO. Vajrakarur pipe indicated spinels of
S1, S3, S4, S5 and S10 groups and the presence of S1 and S2 spinels suggests that the diatreme is of diamondiferous in nature.
The Fe/Fe+Mg and Cr/Cr+Mg ratio percentage of the chrome spinels from Majhgawan range between 48.62 to 64.77 and 83.41 to 92.94 respectively and chrome spinels fall in the field where chrome spinel is intergrown with, or included in diamond. The cluster analysis of Majhgawan indicated S1, S2, S3, S4, S6 and S9 groups and S1 and S2 spinels are diamond indicators.
Studies carried out by Ravishankar 2002 show magnetite, magnesiochromite and titanomagnetite constitute the spinel phase. The Cr/(Cr+Al) and Fe+2/(Fe+2 + Mg) ratios in magnetites range from 0.27 - 0.67 and 0.79 - 0.98 respectively. On the other hand magnesiochromites have Cr/(Cr + Al) ratios 0.9 and the Fe+2/(Fe+2 + Mg) ratios ranging from 0.52 - 0.98. Plots of data on analyzed spinels on Cr/(Cr + Al) versus Fe+2/(Fe+2 + Mg) and Ti/(Ti + Cr + Al) versus Fe+2/(Fe+2 + Mg) indicate that they have the characteristics of both S1 and S2 spinels (Ravishankar et al, 2002).
According to Ravishankar et al, 2002 rutile occurs as microphenocrysts and also as microlites in the groundmass of the Majghawan rock and on analysis it has been found to be hving 84-96 wt % TiO2, appreciably lower (<1 wt%) contents of MnO and NiO. Both Cr2O3 and total iron (expressed as FeO) are low (ranging from 0.16 - 0.40 and 0.67 - 1.62 wt % respectively). Zr concentrations in the same grain range from 0.0 - 0.08 whereas analyses of rutile from surface sample of Majhagawan mine contain 1.11 - 2.77 wt% ZrO2.
Description of Diamonds
Diamonds recovered from the Majhgawan pipe as well as from conglomerate and gravels of the Panna diamond belt are mostly in good crystals shapes. The only difference between the kimberlite diamonds and the conglomerate/gravel diamonds is that in later case the edges of diamonds are more rounded and some diamonds are frosted. The typical crystal form is a combination of octahedron and dodecahedron forms. The octahedrons have sharp edges. A larger majority of the modified forms indicate signs of resorption. Flats and twinned crystals (macles) are also common (Chatterjee & Rao, 1992).
EASTERN GROUP
The eastern group comprises the area from Chhotanagpur plateau to various places in Bastar regions. The eastern group further continues in the Mahanadi river basin in the neighbourhood of Sambalpur district of Orissa as well as Raipur district of the newly formed Chhatisgarh State.
The Chhatisgarh region has been described as the potential zone for diamond occurrences (Mathur, 1981). The area falls within the intracratonic Chhattisgarh basin and Khariar basin area on Bastar Craton (BC). Geological formations and tectonic setting of BC has been proved to be potential for kimberlitic emplacement (Sarkar et al, 1980). The diatreme facie kimberlite is intrusive into basement granite/granite gneisses and is emplaced in close vicinity ENE-WSW trending Behradih lineament.
During the late 1980’s, villagers in the Mainpur area situated 150 km southeast of Raipur, located occurrences of diamond. This was bought to the attention of the authorities. Subsequently fieldwork by the Geological Survey of India (GSI) and the Madhya Pradesh Directorate of Geology and Mining (“DGM”) resulted in the discovery of four kimberlite diatremes. The diatremes were named after local village viz. Payalikhand, Behradih, Kodomali and Jangra.
Every study by the GSI and DGM indicated the possibility of the diatremes containing appreciable quantities of diamond (Chatterjee et al., 1992). In addition field reconnaissance suggested the likelihood of other diatremes being located. The discovery area was subsequently named the Raipur Kimberlite Field (RKF).
Another kimberlite called Kosambura kimberlite (20°10’N: 82°12’E) located 800 metres east of the village of Kosambura has been found recently. The follow up of very strong stream sediment heavy mineral indicator assemblages led directly to a small outcrop of kimberlite within a tertiary drainage feature. The Temple kimberlite (20°12’N: 82°11’E) is located 1300m to the west of Behradih pipe and is named after a nearby roadside temple. This diamtreme was also found primarily by the follow- up of positive mineral indicator assemblages in streams; but in this case no outcrop was observed. The diatreme was finally located by a ground geophysical survey, followed up by shallow pitting into identifiable weathered kimberlite (Small & Vaidya, 2002).
It is highly likely that more kimberlite bodies will be found, once analysis of all samples is completed and further follow-up work begins in earnest.
The Behradih kimberlite (20°12’N: 82°12’E) is located at a distance of 1.5 km south east of Behradih village, which, in turn, is located at a distance of 158 km from Raipur the capital of Chhattisgarh, on Raipur-Deobhog State.

Geology
Mishra et al., 1989, have described the regional geology of Behradih in Raipur District. The Archaean rocks are represented by granite/granite-gneisses with enclaves of chloriteschist, Banded Magnetite Quartzite (BMQ) and quartz mica schist. These in turn, are unconformably overlain by middle to upper Proterozoic Pairi Group of chemoclastic sediments of Khariar basin, represented by sandstone, shale and limestone. Tectonically, the Archaean crystalline rocks of Bastar Craton are in faulted contact with rocks of Eastern Ghat Mobile Belt. The southern extension of Khariar basin is truncated by the major lineament named as Sondhur lineament that Recent - Sub Recent Soil, Laterite
Intrusive Kimberlite
Quartz vein,
Basic dyke and
Aplite with
enclaves of schists,
amphibolite &
Banded Magnetite
quartzite
Archaeans Granite/Granite gneises
Owing to their mostly Precambrian antiquity, unless capped and protected by a cover sequence, the majority of kimberlite pipes in India have been eroded to a deeper level of erosion, some time even up to the root zone of the pipes. Keeping in view the erosional history of the kimberlite pipes, it is expected to locate good secondary diamond deposits in weathered product and at suitable trap locations in the valleys draining the area (Khatediya et al 2002).
The level of erosion of diamondiferous kimberlite pipe rocks effectively controls the amount of placer diamond expected in the weathered profile. A diamondiferous pipe rock, where level of erosion is only up to crater facies would contributes less amount of diamond in placer deposits than those that are eroded up to root zone (Khatediya et al., 2002). The pipe rocks, with level of erosion upto diatreme facies, are also expected to contribute a good amount of diamond to placer occurrences. Chemical analysis of all the four pipes had indicated them to be highly enriched in diamond. The Paylikhand, Jangra and Behradih pipes indicate level of erosion up to diatreme facies, while the Kodomali pipe is eroded up to the root zone. Obviously, the liberated diamonds are presently re-distributed to occur somewhere as placers. The Kasijhar nala is the only major drainage (with its tributaries) carrying the loads of weathered kimberlite rocks to appropriate natural trap sites. The Kasijhar nala joins the Indrawn River, which in turn joins the Udyanti River to transport the sediments further down stream.
The diamondiferous kimberlites have been eroded up to diatreme facies and hence, good amount of diamond might have been carried away through transporting agencies to favourable sites of concentration. The colluvial and alluvial zones, palaeo-channel, meanders, braided channels, weathered sediments etc. are the possible target for the placer deposits. The Raipur district of Chhattisgarh State has much potential for future diamond exploration program.

PRESENT POSITION AND CONCLUSION
Mining in the three groups viz. southern, northern and eastern is being carried out as open pit type. Underground mining has not been done so far. Many of the Multinational companies like De Beers, Rio Tinto, BHP Billiton, Oropo Limited and others have started large scale prospecting for diamonds in the eastern and southern regions of India. De Beers is spending some $5 million on diamond exploration in India. With new techniques like airborne geophysical surveys for locating diamond deposits, India might once again have large quantities of rough diamonds.
If the prospecting and exploration for diamonds is successful, then India shall once again have large indigenous supply of rough diamonds. India already has large diamond cutting factory facilities and jewellery manufacturing units. Besides, there is also a population of one billion as ready market.
In fact, the second half of the 20th century witnessed a tremendous and unchequered growth of the gem and jewellery trade and industry in India. Codified figures from the Gem & Jewellery Export Promotion Council, show that in the year 1969 the exports of gem and jewellery items from India were only a meager amount of US$ 3 million. In 2004 the export figures are US$11.98 billion of which US$ 8.62 billion accounts for diamond exports. This astronomical figure shows that India is recognized as one of the leading suppliers of polished diamonds to the world market. Besides diamond has always been part of the Indian tradition and culture.
India imports rough diamond from major sources like DTC and Argyle through their sights, in addition to the supply obtained directly from the open markets in Antwerp and other places. India cuts and polishes more than 60% of the annual world production of diamonds. The import of rough diamond for this fiscal year is to the tune of 185.27 million carats and is much more than the world production of diamonds, which is approximately 120 million carats. Today, Indian diamond industry cuts and polishes 9 out of every 10 diamonds sold in the world market. The diamond industry employs more than 1,000,000 skilled artisans for cutting and polishing of diamonds. In the last ten years India’s diamond and jewellery industry has overtaken many of the world’s more developed and established centers (IDEX, 2003). These days with computerized tracking systems, cutting-edge laser technology and machines like Sarin are seen with smaller manufacturers. Besides many of the exporters have spread their tentacles and opened offices in every major diamond center in the world. This has given added boost to the growing industry.
Diamond studded jewellery has suddenly developed in leaps and bounds. De Beers with their higher emphasis on diamond promotion in India has borne fruit. Jewellery for exports and jewellery for domestic market are emerging as major segments. The annual consumption of gold in India is more than 800 tons of which 300 tons is fabricated in jewellery for exports. In recent times the demand for diamond-studded jewellery has increased, with modern casting techniques using less quantity of gold. India is now emerging as a major market for studded diamond jewellery.
In concluding the topic, we wish to state that more than 2500 years ago, India was the first to give to the world the most precious treasure on earth viz. diamond. India supplied large diamonds to all corners of the globe. In the saga of time we almost lost the record of the journey of Indian diamonds till the 17th century. However from the 17th century India again enjoyed for some time a prominent position in the world map of diamonds.
Today in this new millennium India is the leader in manufacturing of cut and polished diamonds and retains the position as the largest supplier of faceted diamonds to the world market.
Acknowledgement
The authors express thanks to the National Mineral Development Corporation Ltd., Hyderabad and Panna for their support and permission to take photographs, to the Department of Geology and Mining, Raipur and Geological Survey of India. The authors are grateful to Mr. Somanath Deshmukh for his various interesting inputs and photographs of the southern group. Special thanks are extended to the staff and members of the Gemmological Institute of India.
REFERENCES
» Anil Kumar, and Gopalan, (1992) : Precise Rb. Sr. ages of South Indian Kimberlites and Central Indian Lamproites, Tech. Paper, Intr. Round Table Conference on Diamond Exploration and Mining. New Delhi NMDC.
» Babu T. M. (1998) : Diamonds in India - Geological Society of India.
» Bruton E., (1978) : Diamonds N.A.G Press, London.
» Chatterjee A. K. and Rao, K.S. (1992) : Majhgawan diamondiferous pipe (Madhya Pradesh India) - A geological appraisal. Tech. Paper Intr. Round Table conference on Diamond Exploration and Mining, New Delhi, NMDC.
» Ghosh R. N. and Soni M. K. (2002) : Geochemistry of Majhgawan and Hinota Diatremes, Abs. Vol. Int. Conf. Diam. Gem., Raipur, India.
» IDEX Magazines, (November, 2003) : Idex Online Ltd., Israel.
» Janse. A. J. A. (1992) : Archon and Craton. Modern ideas on tectonic and structural control of economic kimberlites. Tech. paper, Intr. Round Table conference on Diamond Exploration and Mining, New Delhi, NMDC.
» Khatediya M. S. and Verma Promod K. (2002) : Exploration strategy for placer diamonds in Mainpur-Deobhog Area, Chhattisgarh State, India: Abs. Vol. Int. Conf. Diam. Gem., Raipur, India.
» Lenzen G, (1983) : Diamonds and Diamond Grading - Butterworths.
» Maillard R, (1980) : Diamonds - Myth, Magic and Reality
» Mathur, S. M. (1981) : The Diamond deposits of India, Presidential Address.Ind. Science Congress Assn. 30p.
» Mukherjee, Abhijeet (2002) : Compositional Character of Spinels from Wajrakarur Pipe-10 (Anumpalle) and Majghawan, India, Abs. Vol. Int. Conf. Diam. Gem., Raipur, India.
» Ravi Shanker, Nag S. and Rawat B. P. (2002) : Nomenclatural problems in Kimberlites. A case study from Majhgawan, Panna District, Madhya Pradesh, India, Abs. Vol. Int. Conf. Diam. Gem., Raipur, India.
» Sarkar A, Sarkar G, Paul D. K. and Mitra ND, (1990) : Precambrian Geochronology of the Central Indian Shield: A Review; GSI. Spl. Pub. No. 28: pp 453-482.
» Satyanarayana S. V. (2002) : Diamond mining and trade in medieval India : Abs. Vol. Int. CofiT. Diam. Gem., Raipur, India.
» Scott Smith, B. H. (1989) : Lamproites and kimberlites in India, Neues Jarbuch Mineral Abh. V. 161, pp. 193-225.
» Scott Smith B. H. (1992a) : Kimberlites and Lamproites compared and contrasted Tech. Paper. Intr. Round Table conference on Diamond Exploration and Mining, New Delhi, NMDC.
» Sinor, K.P. (1930) : The Diamond mines of Panna State in Central India. The Times of India Press. Bombay 189p.
» Small M. D. and Vaidya A., (2002) : Field exploration for Diamond, Raipur Area, Chattisgarh : Abs. Vol. Int. Conf. Diam. Gem., Raipur, India.
» Smith, C. B. (1992) : In The age of the Majhgawan pipe India, Rep. No. SS P-92-20/2 Scott Smith Petrologyp 9.
» Soni M. K., Jha D. K., Tiwari Mukul, Singh A.N., Agasty Ananda and Pimprikar S.D. (2002) : Geochemical prospecting for Kimberlite in Panna Diamond Belt, M. P., Abs. Vol. Int. Conf. Diam. Gem., Raipur, India,
For further information contact
Dr. Jayshree Panjikar / Mr. K. T. Ramchandran
Gemmological Institute of India
29, Gurukul Chambers, 187-189 Mumbadevi Road,
Mumbai-400 002. E-mail : gemforum@giionline.com
NORTHERN GROUP
The Northern Group of workings lie between the rivers Ken and Sone. The ancient workings were mostly alluvial gravels and exposed conglomerates. The most famous area was the Panna Diamond mines and it was under the Mughal rule. The famous diamonds AKBAR, SHAH OF PERSIA, AGRA and SWAN were found here.
In Panna area, records of diamond mining goes back to the 16th century A.D. Most of the shallow gravels (alluvial and lateritic) as well as the exposed conglomerates were worked. In 1956, the Geological Survey of India (GSI) and the Indian Bureau of Mines (IBM) undertook surface sampling in the kimberlite pipe. 14 pits on 75m square grids were dug to establish surface dimension of the pipe and diamond incidence, six of which were subsequently deepened by National Mineral Development Corporation Limited (NMDC).
Till 1959, diamond mining was under a private party viz.M/s. Panna Diamond Mining Syndicate. Presently studies are being carried out to increase the production that will require mining and processing of about one million tones of tuff.
Geology
The only regular diamond producing mine in the country is the Majhgawan pipe in Panna district, Madhya Pradesh and located 15km WSW of Panna town. The pipe occurs in an ideal geologic and tectonic setting favourable for emplacement of alkaline ultrabasic diatremes. The pipe is intrusive into intracratonic basin of platform sediments of the Vindhyan Supergroup of Upper Proterozoic age. Immediately to the north lies the Bundelkhand craton of Archaean basement which is composed primarily of granites and granite gneisses with small enclaves of older metamorphics and basic and ultrabasic intrusive. The basement rock is overlain by the rocks of the Vindhyan Supergroup, which consist mainly of sandstone, shale and limestone etc. (Mathur, 1981).The generalized geological sequence in Panna area is given belowIndian Diamond Mines are grouped as Rough Diamond from Panna Diamond Mines Rough Diamond Crystal from Panna Mines
Panna Diamond Mines (Majghawana)
The Chhatisgarh region has been described as the potential zone for diamond occurrences (Mathur, 1981). The area falls within the intracratonic Chhattisgarh basin and Khariar basin area on Bastar Craton (BC). Geological formations and tectonic setting of BC has been proved to be potential for kimberlitic emplacement (Sarkar et al, 1980). The diatreme facie kimberlite is intrusive into basement granite/granite gneisses and is emplaced in close vicinity ENE-WSW trending Behradih lineament.
During the late 1980’s, villagers in the Mainpur area situated 150 km southeast of Raipur, located occurrences of diamond. This was bought to the attention of the authorities. Subsequently fieldwork by the Geological Survey of India (GSI) and the Madhya Pradesh Directorate of Geology and Mining (“DGM”) resulted in the discovery of four kimberlite diatremes. The diatremes were named after local village viz. Payalikhand, Behradih, Kodomali and Jangra.
extends over a strike length of about 200 km with a general NW-SE trend. This lineament is very significant as a large number of intrusive bodies are reported to occur along this trend.
Local geological set-up of Beradih region in Raipur District is given in Table given below

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