Mineralogy (धातुशास्त्रम्)

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.

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.

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

"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."

The scientific analysis of the archaeological and literary evidences points to the debunking of the aryan invasion myth in the recent times.

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.

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.

Alchemy was one of the chief areas for the exploration of mercurial compounds, as specialists in medicine like Charaka, believed in the search for the ideal rasa or elixir which could prolong life indefinitely. They believed in therapeutic values of organic as well as inorganic materials such as metals and metallic compounds; they also aspired to convert base metals into gold. This alchemical dream was boosted when Nagarjuna claimed (Rasaratnakara - 1.3) that zinc ore roasted thrice with copper converts the latter into 'gold'. However, it was gold-like, brilliant yellow brass that came into existence.

Many textual evidences which speak about gems, minerals and metals include the Rig and Yajurvedic references, Kautilya's Arthashastra, Brhat Samhita of Varahamihira, Rasaratnakara of Nagarjuna, Rasarnava, Ratnapariksha, Rasaratnasamucchaya and Agastimata.

Legend about Origin of Gems

Ratnapariksa and Agastimata narrated the legend that gems had been derived from the body of the slain demon Bala: diamond from his bones, pearl from the teeth, ruby from the blood, sapphire from the eyes, emerald from the bile etc. The mythical bird Garuda had taken the green bile of the demon in its mouth and then vomitted it (hence the name Garutmata and Garudodgaara) on a mountain on the sea- coast near a desert 'beyond Barbara country’. Both Ratnapariksha and Agastimata mentioned Garuda as the ruler of the serpents hence called pannagadhipah. Panna also means something fallen down or dropped. Thus, the dropped bile or the green emerald also came to be known as panna.

In his Brhat Samhita, Varahamihira gave a scientific explanation that the gems were caused by the characteristic qualities of the earth.

रत्नानि बलाद्दैत्याद्दधीचितोऽन्ये वदन्ति जातानि । केचिद्भुवः स्वभावाद्वैचित्र्यं प्राहुरुपलानाम् ।। (Brht. Samh. 80.3)

Meaning: Gems, they say, were born of the bones of the daitya Bala; while others state that they were born of Dadichi; yet others say that the wonderful variety of germs is caused by the characteristic qualities of the earth.

Gem-Minerals

Description of the essential qualities of gems is

वज्रैन्द्रनील-मरकतकर्केतरपद्मरागरुधिरऽख्याः । वैदूर्य[क्.वैडूर्य]पुलकविमलकराजमणिस्फटिकशशिकान्ताः ।।

सौगन्धिक-गोमेदक-शङ्ख-महानील-पुष्परागऽख्याः । ब्रह्ममणि-ज्योतीरस-सस्यक-मुक्ता-प्रवालानि ।। (Brht. Samh. 80.4-5)

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).

The names of many minerals and elements that we find in European languages were originally derived from Samskrit, having strong etymological roots. A few samskrit origins of minerals are as follows.

1. Corundum is derived from "कुरुविन्दः । kuruvinda", meaning that which abrades.
2. Sulphur was derived from "शुल्वारी । Shulvari" meaning that which is enemy (अरिः) of, or reacts with, copper (शुल्वा। Shulva).
3. Beryllium is derived from mineral Beryl. Beryl is derived from the term वैदूर्यम् । Vaidurya or the South Indian term "Veluriya". Panini mentions in his Ashtadhyayi (4.3.84) that the mineral came from Vidura (विदूर) locality in South India (hence termed Vaidurya), identified as Salem district, supported by evidence that mines of Coimbatore used to supply beryl for its export to the Romans. Outside India, Veluriya was called Beryllos (Greek) and Beryllus (Latin) from which the English term Beryl and Beryllium came forth.
4. Emerald - 'मरकतम् । Marakata' in Samskrit gave rise to smaragdos in Greek, smaragdus in Latin, esmeralda in Spanish and emerald in English. Emerald has few more name - equivalents in Sanskrit: Harinmani (green gem), Garudodgdra, Garutmata, Panna etc.

The identity of vaidurya with beryl is well- established. It was known to be quite different from cat’s eye. Kautilya listed beryl vaidurya and cat’s eye marjdraksaka as distinctly separate gems (AS 2.11.30 and 39).

Gem categories of Importance in the Ancient India

Name English	Name Samskrit	Colour	Reasons for non-white colour
Diamond	Vajra (वज्रः)	Colourless	Blue due to boron, yellow/green due to nitrogen
Corundrum	Kuruvinda (कुरुविन्दः)	Colourless	Pure Al2O3 is colourless
Ruby	Padmaraga (पद्मरागम्)	Red	Cr3+ (Chromium ion) replaces Al3+ (Aluminium ion). Transition involving ligandfield effect.
Sapphire	Indranila (इन्द्रनीलः)	Blue	Four different mechanisms including charge transfer, combination of Fe (Iron) and Ti (Titanium)
Chrysoberyl/Cat's eye	Marjarakshaka / Lasunia	Green/ Yellow	Green due to Cr and yellow due to Fe substituting in BeAl2O4 structure
Spinel/Balas-ruby	Balasuryaka	Rose-red	Pure spinel Mg Al2O4 is colourless. Cr3+substitution makes it rose-red. Fe and Mg may further alter the colour.
Topaz	Pushparaga (पुष्परागः)	Yellow	Pure topaz is colourless [Al (F,0H)]2 SiO4. Yellow colour is due to impurities - ferrous oxide, lime and alkali. Dichromic is blue.
Beryl	Vaidurya (वैडूर्यम्)	Faint Green, Water colour	Pure beryl Be3Al2Si6O18 is colourless. Faint green due to substituting Cr3+. This is allochromatic effect - transition involving ligand field.
Emerald	Marakata (मरकतक) Panna	Deep grass green	This is beryl containing more Cr3+ imparting green colour. Dichroic, the second blueish colour is due to iron.
Aquamarine	Paribhadra	Faint blue to bluish green	Bluish tinge due to iron.
Zircon	Gomedhaka (गोमेदकः)	Cow-flesh color	Pure zircon ZrSiO4 is colourless. Reddish-yellow colour of Hyacinth is due to Fe3+ decolourised on reduction to Fe2+.
Garnet	Tamrya or Tamdi	Various colors	Family of minerals M2+3 M3+2(SiO4)3. Colour depends upon chemical composition. Hessonite is confused with Hyacinth. Colour due to iron.
Tourmaline	Vaikranta	Various colors	H9Al3(B.OH)2 Si4O19 pure tourmaline is light coloured. Fe2+ and Cr3+ make it dark green. Mg makes it brown and Mn dark red.
Quartz	Sphatika (स्फटिकः)	Colourless	Pure SiO2 is colourless. Yellow citrine due to iron green chrysoprase due to nickel, violet amethyst due to manganese etc.
Agate	Akik	Light colour	Hydrated SiO2 is colourless. Hydrated ferric oxide as impurity makes it brown or yellow.
Carnelian	Rudhirakhya (रुधिर)	Red	Heating causes dehydration and ferric oxide gives red colour to carnelian.
Olivine/ Chrysolite/ Peridot	Puttika / Jabarjad	Bottle green	Pure Mg2SiO4 is colourless Replacement of part of MgO by ferrous oxide makes it yellowish green. Mn2+ Ni2+ further change the colour.
Orthoclase/Feldspar Moonstone Sunstone	Moonstone (शशिकान्तः । Chandrakanta) Sunstone (Suryakanta)	Opalescent play of colour	Interference of light from thin layers.
Jade	Pitu	White green black	Green due to Mn and Cr and Fe2+. Black due to Fe3+
Pearl	Mukta (मुक्ता)	Usually white	Iron, manganese etc.possibly complexed with organic matter, so that the colour is perishable on heating.
Coral	Pravala (प्रवाला) / Vidruma	red, black	Iron, manganese etc.possibly complexed with organic matter, so that the colour is perishable on heating.

A few non-gem minerals of commercial importance in ancient India:

adrija (bitumen), abhraka (mica), kajjali (cinnabar), karpurarasa (calomel), kamksi (alum), kasisa (green vitriol or ferrous sulphate), kharpara (zinc ore), gandhaka (sulphur), gandhara (red lead), chulika lavana (sal ammoniac), tankana (borax), tala (orpiment), tutthaka (blue vitriol), nilanjana (stibnite), makaradhvaja (mercuric sulphide), manahsila (realgar) maksika (pyrite), swarnamakshika (chalcopyrite), mrddarasrnga (anglesite or litharge), rasaka (calamine), rasakarpura (mercuric chloride), rasasindura (mercuric sulphide), rasanjana (stibnite), varatika (marine nodule), vahnimrttika (fire-clay), vimalaka (pyrite), kamsya vimala (arsenopyrite), silajatu (bitumen), sarjika mrttika (river-bed alkaline reh), sasyaka (blue vitriol), sisaja (red lead), suvarcika (borax), srotanjana or sohta (carrollite), haritala (orpiment) etc.

The commonly used eight metals in antiquity are gold, silver, copper, iron, tin, lead, zinc and mercury.

The Ores of Metals

Gold and Silver: Early reference to gold is to be found in the Rigveda samhita. The noble metals, gold and silver, are found in the native state, and were used to make jewellery and sheet metal due to the great ductility and lustre of the pure metals. In ancient times, gold was collected by panning alluvial sands from placer deposits. However, India has the distinction that the deepest ancient mines in the world for gold come from the Maski region of Karnataka with carbon dates from the middle of the first millennium BC. Interestingly, as far as silver production goes, the Aravalli region in North-West India ranks amongst the few major ancient silver producing sites in the world.

Copper: Early copper artifacts are reported from the pre-Indus valley sites of Baluchistan, the northwestern part of Indian subcontinent. Evidence of ancient mining of copper ores was from the Khetri region of Rajasthan in India dating to about 3rd-2nd millennium BC. Huge quantities of copper objects such as blades, arrow-heads, fish hooks were found from the sites of Pre-harappan excavations. It may be asserted based on evidence that copper metallurgy was developed indigenously in the Indian subcontinent well before 4000 BC.