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| Mineralogy (Samskrit: धातुशास्त्रम्) or metallurgy discusses the chemistry of Dhatus (minerals), their properties, composition, reactions, combination products namely alloys and their uses. A related topic, mining of metals, involves the chemistry of extraction from ores, smelting and forging activities. History of mining in the Indian subcontinent can be traced back to pre-Harappan period where the evidence of earliest settlements of farming communities using metal implements have been found.<ref name=":0">Singh. R. D, (1997) ''History of Technology in India, Vol. 1, From Antiquity to c. 1200 A.D. by A. K. Bag.'' New Delhi: Indian National Science Academy. (Chapter Mining: Page 48 - ) </ref> | | Mineralogy (Samskrit: धातुशास्त्रम्) or metallurgy discusses the chemistry of Dhatus (minerals), their properties, composition, reactions, combination products namely alloys and their uses. A related topic, mining of metals, involves the chemistry of extraction from ores, smelting and forging activities. History of mining in the Indian subcontinent can be traced back to pre-Harappan period where the evidence of earliest settlements of farming communities using metal implements have been found.<ref name=":0">Singh. R. D, (1997) ''History of Technology in India, Vol. 1, From Antiquity to c. 1200 A.D. by A. K. Bag.'' New Delhi: Indian National Science Academy. (Chapter Mining: Page 48 - ) </ref> |
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− | Bharatavarsha is known for its use of gold and silver for jewelry and making ornamental vessels for domestic use with silver. Copper tools, such as axes, sickles are found in many archaeological sites indicating that many farming tribes and agricultural communities were using them. Metallurgy of copper and its alloys (brass and bronze) was highly developed during this period. A remarkable use of brass was made in the constructional work of an unfinished Vihara made near Nalanda (Bihar). Thus many archaeological revelations have unearthed valuable knowledge pertaining to sulbashastra (geology) and dhatushastra (metallurgy) of the ancients.<ref name=":0" /> [[File:Sushruta's Surgical Tools Made of Iron.PNG|thumb|Ancient Surgical tools in India|450x450px]] | + | Bharatavarsha is known for its use of gold and silver for jewelry and making ornamental vessels for domestic use with silver. Copper tools, such as axes, sickles are found in many archaeological sites indicating that many farming tribes and agricultural communities were using them. Metallurgy of copper and its alloys (brass and bronze) was highly developed during this period. A remarkable use of brass was made in the constructional work of an unfinished Vihara made near Nalanda (Bihar). Thus many archaeological revelations have unearthed valuable knowledge pertaining to sulbashastra (geology) and dhatushastra (metallurgy) of the ancients.<ref name=":0" /> [[File:Sushruta's Surgical Tools Made of Iron.PNG|thumb|Ancient Surgical tools in India|475.234x475.234px]] |
| == Introduction == | | == Introduction == |
| Metals, Minerals and ores are mentioned by the terms dhatu (धातुः) khanija (खानिजम्) and the chemistry involved is termed Khanija-rasayana (खानिजरसायनम्). A mineral is defined in modern terms as follows<ref name=":1">''[http://eprints.nmlindia.org/5802/1/1-24.PDF Minerals and Their Exploitation in Ancient and Pre-modern India]'' by Prof. A. K. Biswas</ref><blockquote>''"As we knew mineral is a naturally occurring crystalline element or a compound having definite chemical composition, and formed as a product of inorganic processes."''</blockquote>The scientific analysis of the archaeological and literary evidences points to the debunking of the aryan invasion myth in the recent times.<ref name=":1" /> <blockquote>''A number of experts have concluded that the collapse of the Harappan civilization was not on account of any 'foreign invasion' but essentially due to repeated floods, tectonic movement leading to the drying up and disappearance of the Sarasvati river, civil war, loss of trade etc.''</blockquote>Just like pottery, metals in antiquity is also linked to the history of a civilization. In the ancient past, the first metals to be utilized were those found in the native or elemental state, and then progressively those metals were used which could be easily extracted or smelted from their ores. The smelting of metals, which were more difficult to extract from ores, was mastered later. Most of the metals and elements indicated in the Periodic Table were in fact identified only in the last few centuries. | | Metals, Minerals and ores are mentioned by the terms dhatu (धातुः) khanija (खानिजम्) and the chemistry involved is termed Khanija-rasayana (खानिजरसायनम्). A mineral is defined in modern terms as follows<ref name=":1">''[http://eprints.nmlindia.org/5802/1/1-24.PDF Minerals and Their Exploitation in Ancient and Pre-modern India]'' by Prof. A. K. Biswas</ref><blockquote>''"As we knew mineral is a naturally occurring crystalline element or a compound having definite chemical composition, and formed as a product of inorganic processes."''</blockquote>The scientific analysis of the archaeological and literary evidences points to the debunking of the aryan invasion myth in the recent times.<ref name=":1" /> <blockquote>''A number of experts have concluded that the collapse of the Harappan civilization was not on account of any 'foreign invasion' but essentially due to repeated floods, tectonic movement leading to the drying up and disappearance of the Sarasvati river, civil war, loss of trade etc.''</blockquote>Just like pottery, metals in antiquity is also linked to the history of a civilization. In the ancient past, the first metals to be utilized were those found in the native or elemental state, and then progressively those metals were used which could be easily extracted or smelted from their ores. The smelting of metals, which were more difficult to extract from ores, was mastered later. Most of the metals and elements indicated in the Periodic Table were in fact identified only in the last few centuries. |
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| It is interesting to note that ancient texts have mentioned many matters regarding the existence and usage of metals, their properties, nature and their extraction. Debiprasad Chattopadhyaya acclaimed [[Uddalaka (उद्दालकः)|Uddalaka Aruni]] as ''''the first scientist in the world'''<nowiki/>'. Uddalaka Aruni as mentioned in the Chandogya Upanishad propounded that everything in the universe including man evolved out of three elements, and even mind is a product of matter. According to Chattopadhyaya Maharshi Uddalaka preceded Theles of Greece by nearly two centuries.<ref name=":1" /><ref>Chattopadhyaya, Debiprasad. (1991) ''History of Science and Technology in Ancient India ll Formation of the Theoretical Fundamentals of Natural Science.'' Calcutta: Firma KLM Pvt. Ltd., </ref> | | It is interesting to note that ancient texts have mentioned many matters regarding the existence and usage of metals, their properties, nature and their extraction. Debiprasad Chattopadhyaya acclaimed [[Uddalaka (उद्दालकः)|Uddalaka Aruni]] as ''''the first scientist in the world'''<nowiki/>'. Uddalaka Aruni as mentioned in the Chandogya Upanishad propounded that everything in the universe including man evolved out of three elements, and even mind is a product of matter. According to Chattopadhyaya Maharshi Uddalaka preceded Theles of Greece by nearly two centuries.<ref name=":1" /><ref>Chattopadhyaya, Debiprasad. (1991) ''History of Science and Technology in Ancient India ll Formation of the Theoretical Fundamentals of Natural Science.'' Calcutta: Firma KLM Pvt. Ltd., </ref> |
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| == Gem - Minerals == | | == Gem - Minerals == |
| Earliest complete description of the gems is given in texts such as Arthashastra and Brhat Samhita.<blockquote>वज्रैन्द्रनील-मरकतकर्केतरपद्मरागरुधिरऽख्याः । वैदूर्य[क्.वैडूर्य]पुलकविमलकराजमणिस्फटिकशशिकान्ताः ।। </blockquote><blockquote>सौगन्धिक-गोमेदक-शङ्ख-महानील-पुष्परागऽख्याः । ब्रह्ममणि-ज्योतीरस-सस्यक-मुक्ता-प्रवालानि ।। (Brht. Samh. 80.4-5)</blockquote>Meaning: The following are the gems: Vajra (Diamonds), Indranila (Sapphire), Marakata (Emerald), Arkata (Agate), Padmaraga (Ruby), Rudhira (Blood-stone), Vaidurya (Beryl), Pulaka (Amethyst), Vimalaka, Rajamani, Spatika (Quartz), Shashikanta (moon-gem), Saugandhika, Gomedaka (Zircon), Shankha (Conch Shell), Mahanila (Azure), Pushparaga (Topaz), Brahma-mani, Jyoteerasa, Sasyaka, Mukta (Pearl), Pravala (Coral).<ref name=":3" /> | | Earliest complete description of the gems is given in texts such as Arthashastra and Brhat Samhita.<blockquote>वज्रैन्द्रनील-मरकतकर्केतरपद्मरागरुधिरऽख्याः । वैदूर्य[क्.वैडूर्य]पुलकविमलकराजमणिस्फटिकशशिकान्ताः ।। </blockquote><blockquote>सौगन्धिक-गोमेदक-शङ्ख-महानील-पुष्परागऽख्याः । ब्रह्ममणि-ज्योतीरस-सस्यक-मुक्ता-प्रवालानि ।। (Brht. Samh. 80.4-5)</blockquote>Meaning: The following are the gems: Vajra (Diamonds), Indranila (Sapphire), Marakata (Emerald), Arkata (Agate), Padmaraga (Ruby), Rudhira (Blood-stone), Vaidurya (Beryl), Pulaka (Amethyst), Vimalaka, Rajamani, Spatika (Quartz), Shashikanta (moon-gem), Saugandhika, Gomedaka (Zircon), Shankha (Conch Shell), Mahanila (Azure), Pushparaga (Topaz), Brahma-mani, Jyoteerasa, Sasyaka, Mukta (Pearl), Pravala (Coral).<ref name=":3" /> |
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| Arthashastra describes the qualities of the lead ore thus<blockquote>काक-मोचकः कपोत-रोचना-वर्णः श्वेत-राजि-नद्धो वा विस्रः सीस-धातुः ।। ०२.१२.१३ ।। (Arth. Shast. 2.12.13)<ref name=":6" /></blockquote>''"Those ores which have the colour of kákamochaka (Solanum Indica), pigeon, or cow‟s bile, and which are marked with white lines and smell like raw meat are the ores of lead."''<ref name=":7" /> | | Arthashastra describes the qualities of the lead ore thus<blockquote>काक-मोचकः कपोत-रोचना-वर्णः श्वेत-राजि-नद्धो वा विस्रः सीस-धातुः ।। ०२.१२.१३ ।। (Arth. Shast. 2.12.13)<ref name=":6" /></blockquote>''"Those ores which have the colour of kákamochaka (Solanum Indica), pigeon, or cow‟s bile, and which are marked with white lines and smell like raw meat are the ores of lead."''<ref name=":7" /> |
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− | The lead artifacts during the Harappan period reflect the fact that people were acquainted with lead ores (such as galena) and their smelting process which is simple on account of easy reducibility and low melting point of the metal. Like gold and silver, lead did not find extensive usage in tools and implements owing to its softness. It is one of the softest and heaviest metal having shining grey lustre which leaves a black streak on paper. | + | The lead artifacts during the Harappan period reflect the fact that people were acquainted with lead ores (such as galena) and their smelting process which is simple on account of easy reducibility and low melting point of the metal. Like gold and silver, lead did not find extensive usage in tools and implements owing to its softness. It is one of the softest and heaviest metal having shining grey lustre which leaves a black streak on paper. It is so soft that it can be scratched even with nail hence it’s use has been mostly for the manufacture of cheap jewellery dies or pattern for shaping other metals, and as a hardner in copper alloys. |
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− | It is so soft that it can be scratched even with nail hence it’s use has been mostly for the manufacture of cheap jewellery dies or pattern for shaping other metals, and as a hardner in copper alloys. | |
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| ==== Extraction Process ==== | | ==== Extraction Process ==== |
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| Mercury is a metal that has been of great alchemical importance in ancient times. It is a volatile metal, which is easily produced by heating cinnabar followed by the downward distillation of mercury vapour. Some of the earliest literary references to the use of mercury distillation come from Indian treatises such as the Arthashastra of Kautilya. Ayurvedic texts have presented the science of using mercury, as [[Rasashastra (रसशास्त्रम्)|Rasashastra]]. | | Mercury is a metal that has been of great alchemical importance in ancient times. It is a volatile metal, which is easily produced by heating cinnabar followed by the downward distillation of mercury vapour. Some of the earliest literary references to the use of mercury distillation come from Indian treatises such as the Arthashastra of Kautilya. Ayurvedic texts have presented the science of using mercury, as [[Rasashastra (रसशास्त्रम्)|Rasashastra]]. |
| * Sindhur or Vermilion was Cinnabar, mercuric sulphide, was used to make the red/maroon mark on the forehead as described by Charaka. | | * Sindhur or Vermilion was Cinnabar, mercuric sulphide, was used to make the red/maroon mark on the forehead as described by Charaka. |
− | [[File:Delhi Iron Pillar.png|thumb|Delhi Iron Pillar " The Rustless Wonder"]] | + | [[File:Delhi Iron Pillar.png|thumb|Delhi Iron Pillar " The Rustless Wonder"|489.961x489.961px]] |
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| === अयस् ॥ Iron (''Ferrum - Fe'') === | | === अयस् ॥ Iron (''Ferrum - Fe'') === |
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| Iron supplemented copper in the preparation of various tools for hunting and agriculture, apart from household objects and building materials. A survey of ancient literature has provided ample evidence that iron and steel making technology and their difference has been known in the Vedic period (based on references in Rgveda and Yajurvedd) and may be even earlier.<ref name=":5" /> | | Iron supplemented copper in the preparation of various tools for hunting and agriculture, apart from household objects and building materials. A survey of ancient literature has provided ample evidence that iron and steel making technology and their difference has been known in the Vedic period (based on references in Rgveda and Yajurvedd) and may be even earlier.<ref name=":5" /> |
| + | [[File:Iron Smelting Furnace.PNG|thumb|450x450px|Sketch of the reconstructed Iron Smelting Furnace dating to 700 B.C]] |
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| ==== Extraction Process ==== | | ==== Extraction Process ==== |
− | * Ores of Iron : Haematite (Fe<sub>2</sub>O<sub>3</sub>), Magnetite (Fe<sub>3</sub>O<sub>4</sub>), Goethite (HFeO<sub>2</sub>) and Limonite (FeO (OH)<sub>n</sub>*H<sub>2</sub>O). | + | * Ores of Iron : Haematite (Fe<sub>2</sub>O<sub>3</sub>), Magnetite (Fe<sub>3</sub>O<sub>4</sub>), Pyrite (FeS) |
| + | * Smelting of Iron by ancient reduction processes |
| + | * Satvapaatana: Extraction of iron from Biotite by Ayurvedic method called Satvapaatana. |
| + | * Carburization and Steel Production (iron carbon alloying) by two processes |
| + | In Bihar, Orissa, and Eastern part of Karnataka the iron smelting was carried out by community called "Asura" and in Central India by the "Aagaria" tribes. While Aagarias smelted the iron ore to produce wrought iron blooms "Lohars" shaped the rough iron to manufacture various tools and objects. Other tribes in India such as Mundias were also involved in smelting of Iron. A number of furnaces have been found at Nalanda, Naikund, Khairadih, Ujjain and many sites in India. Development of reusable furnaces was seen over time. |
| + | |
| + | ==== Ancient Smelting Method ==== |
| + | Tradition describes the ancient iron making process which was considered a sacred ritual and the secret of smelting process was highly guarded, transmitted only to the younger generation from the family or tribe. Women also had an active role to play and were designated to do specific jobs in the process. The operation was carried out near ore deposit or in the nearby forest to procure the required wood. The whole operation of the furnace can be divided into five parts<ref name=":5" /> |
| + | # Collection and preparation of the raw-material : Experienced elders located the suitable deposit of the ore after the due rituals and pujas are performed. Women helped in breaking and transporting the ore. Charcoal was prepared from wood like Irool (Xylia dolaberiformis) Teak, Babul (Acacia arbica), Sal (Shorearubusta), Bamboo (Caleotropis gigantica) etc. yielding dense and heavy charcoal. They also maintained the outside of the furnace and stored sufficient quantity of water. |
| + | # Making of the furnace and its dressing : These furnaces were called Bhatti, Kothi or Kosthi and made from locally available clay, and at many places internally lined with natural china clay or a refractory mixture generally used for crucible manufacture. Different kinds of furnaces were made either below the ground level, or on the sloping face of a hillock or above ground level. All furnaces had two holes - one for introducing the blast and other for removing the molten slag. The construction of the furnaces involved many design principles ranging from the clay used, the drying and repatching of the walls, the mathematical aspects such a height, width or slants of the furnace, the specific sizes of the openings at the bottom, the location of the bellows and peep holes to monitor temperature. |
| + | # Making of air bellows and their fitting : Air to the furnace is provided by a pair of small bellows made of goat or buffalo skin and connected to the furnace through the bamboo and clay pipes operated by a single person. In later times the size of the bellow was increased but it was maintained so as ancients realized that blowing excess air leads to production of brittle cast iron and not solid sponge or wrought iron. |
| + | # Ignition of the furnace and its operation : Once the furnace was ignited after the required preparation with charcoal, bellows were operated to raise the temperature at slow pace. When the furnace was red hot and CO gas was seen burning at the top, the furnace was charged with pre-heated ore and charcoal in alternate layers. The preheating of the ore was done by storing it on the inclined platform. As the maximum temperature was achieved at the tuyere level, by increased air blowing, a small hole was made in the front wall to tap out the molten Fayalite slag. The reduced sponge iron gets consolidated in the hearth by partial fusion, the block of which is removed by breaking the front wall of the furnace. |
| + | # Handling of the sponge iron. The hot iron bloom taken out of the furnace is hammered on stone anvil to squeeze out liquid slag before it gets solidified. It is subjected to further heating and refining process. |
| + | |
| + | ==== Ayuvedic Method ==== |
| + | In Rasa Ratna Samuccaya and other Ayurvedic text a number of processes have been mentioned for the extraction of iron from Biotite and other iron bearing minerals for the preparation of medicine. This process is known as Satvapaatana, and generally consists of three major steps : (i) Shodhana (purification), (ii) Bhaavana (Maceration and Trituration) (iii) Dhamana (Heating and smelting).<ref name=":5" /> |
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| + | ==== Carburization and Steel Production ==== |
| + | The Indian craftsmen had realised the effect of addition of ‘C’ (Carbon) to iron and the excellence of the cutting edges formed on such steel weapons. Wootz steel was being produced in several places in India and exported to the West even as early as 700 B.C. for the manufacture of famous ‘Damascus Swords'. This sword had attained its reputation for edge sharpness, flexibility, strength and the typical surface structure on the sword’s surface. |
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| + | The carburization of hot sponge or bloom could be done by the following techniques:<ref name=":5" /> |
| + | # Increasing the carbon content of the hot sponge inside the smelting furnace by raising the furnace temperature and the retention time of the hot sponge for a slightly longer period. |
| + | # By increasing the temperature and the time of contact between the hot iron bar and charcoal during secondary refining. |
| + | # By selective carburization of cutting edge of the implements by the application of carburizing paste and reheating to 950 to l000<sup>0</sup>C. |
| + | The following two distinct processes have been reported for production of steel from iron. |
| + | # By carburization of wrought iron rods and melting in small crucibles. |
| + | # By decarburization of white cast iron. |
| + | Rasaratnasamucchaya (70-71 shlokas) has given the following classification of iron-carbon alloys. Based on the characteristic features of the fractured surfaces and other properties such as ductility, magnetism and hardness etc, these have been further classified into sub-groups. This type of classification has no parallel in the world. |
| + | * Kaanta Loha (soft iron) |
| + | * Tikshna Loha (high carbon steel) |
| + | * Munda Loha (cast iron) |
| + | |
| + | ==== Tools and Implements ==== |
| '''Surgical tools''' : The Susruta Samhita has mentioned the method of fabrication of more than 100 surgical tools made of Fe-C alloys and the process of heat treatment to obtain razor sharp edge capable of splitting hair into two halves longitudinally. | | '''Surgical tools''' : The Susruta Samhita has mentioned the method of fabrication of more than 100 surgical tools made of Fe-C alloys and the process of heat treatment to obtain razor sharp edge capable of splitting hair into two halves longitudinally. |
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| '''Iron Pillar of Delhi''' : The forging of wrought iron seems to have reached its zenith in India in the first millennium AD. The earliest large forging is the famous iron pillar with a height of over 7 m and weight of about 6 tons at New Delhi ascribed to Chandragupta Vikramaditya 400- 450 CE . The inscription of the Gupta period of the 4th century CE is in Brahmi script of Sanskrit (Figure 8).The pillar is believed to have been made by forging together a series of disc-shaped iron blooms. The Iron Pillar, the earliest and the largest surviving iron forging in the world, is regarded as a metallurgical marvel because it has defied the laws of corrosion of iron even after so many centuries, earning the nickname, the ‘rustless wonder’. Its astounding corrosion-resistance is partly due to its composition; high slag and phosphorus (0.25 p.c.) content and low manganese (0.05) and sulphur (0.005) content.<ref name=":1" /><ref name=":4" /> | | '''Iron Pillar of Delhi''' : The forging of wrought iron seems to have reached its zenith in India in the first millennium AD. The earliest large forging is the famous iron pillar with a height of over 7 m and weight of about 6 tons at New Delhi ascribed to Chandragupta Vikramaditya 400- 450 CE . The inscription of the Gupta period of the 4th century CE is in Brahmi script of Sanskrit (Figure 8).The pillar is believed to have been made by forging together a series of disc-shaped iron blooms. The Iron Pillar, the earliest and the largest surviving iron forging in the world, is regarded as a metallurgical marvel because it has defied the laws of corrosion of iron even after so many centuries, earning the nickname, the ‘rustless wonder’. Its astounding corrosion-resistance is partly due to its composition; high slag and phosphorus (0.25 p.c.) content and low manganese (0.05) and sulphur (0.005) content.<ref name=":1" /><ref name=":4" /> |
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− | '''Wootz Steel''' : Another iron product of repute is the high carbon steel manufactured in the recent past by the crucible process. Wootz is the anglicized version of "ukku" in the languages of the states of Karnataka, and Andhra Pradesh, a term denoting steel. Literary accounts suggest that steel from the southern part of the Indian subcontinent was exported to Europe, China, the Arab world and the Middle East. Studies on Wootz indicate that it was an ultra-high carbon steel with between 1-2% carbon and was used to make the fabled Damascus swords. | + | '''Wootz Steel''' : This iron-carbon alloy of repute is the high carbon steel manufactured in the recent past by the crucible process. It is called Wootz Steel, the anglicized version of "ukku" in the languages of the states of Karnataka, and Andhra Pradesh, a term denoting steel. Literary accounts suggest that steel from the southern part of the Indian subcontinent was exported to Europe, China, the Arab world and the Middle East. Studies on Wootz indicate that it was an ultra-high carbon steel with between 1-2% carbon. |
| + | * Largest and riches deposits of Hematite and Magnetite all over India |
| * The Largest and Earliest Rustless Iron Forging Wonder : Iron Pillar of Chandragupta Vikramaditya at Delhi | | * The Largest and Earliest Rustless Iron Forging Wonder : Iron Pillar of Chandragupta Vikramaditya at Delhi |
| * Wootz Steel prepared by indigenous crucible process. | | * Wootz Steel prepared by indigenous crucible process. |