IKS/ Part 3· Metals and Metalworking Chapter 10 of 14
Part 3 · Chapter 10

Metals and Metalworking

लोहशास्त्रम्

A pillar of iron seven metres tall that has stood in the open air near Delhi for sixteen centuries without rusting through. A steel that European metallurgists spent two hundred years failing to replicate. A method of extracting zinc that requires understanding why the metal must be condensed downwards. This chapter is about the branch of Indian knowledge that left physical objects you can go and look at.

1Three kinds of evidenceप्रमाणत्रयम्

This is the chapter where the “how do you know?” question of chapter 1 has the easiest answers — because much of the evidence is metal, and metal survives.

Three converging lines of evidence for Indian metallurgy Archaeological remains, surviving artefacts still in place, and technical literature. 1 · Archaeology Ancient mine workings, spoil heaps, slag, spent retorts, furnace floors. Slag is particularly informative: its composition tells you the furnace temperature and the process, whatever anybody wrote down. 2 · Surviving objects The Delhi iron pillar. The Konark beams. The Sultanganj Buddha. Chola bronzes. Gupta coinage. These can be weighed, sectioned, analysed and dated. They are the strongest evidence in the chapter. 3 · Literature Rasa-ratna-samuccaya, Rasārṇava, Yukti-kalpataru, the Arthaśāstra's chapters on mines and metals. Plus outside testimony: Herodotus, Ktesias, Pliny, Xuanzang, and Arab writers on the quality of Indian steel.
When all three agree — a text describing a furnace, the remains of that furnace, and an object with the microstructure the process would produce — the conclusion is about as secure as history of technology gets.
A worked example of the three converging

Gold coins of Samudragupta (330–376 CE), now in the British Museum, carry very fine relief. Producing them requires ore location, extraction, refining to a workable purity, and die-striking with hardened dies. That single object implies a mining industry, a refining process, and a tool steel — none of which is mentioned on the coin. Objects testify to the infrastructure behind them.

2Mining and oreखनिः

13th c. BCEearliest underground mining so far dated in India
c. 1000 BCEmining at Zawar, Rajasthan begins
≈15,000 testimated zinc mined and smelted at Zawar over its working life
34.34%zinc in a brass vase from Taxila — above what cementation alone can reach

Modern mining companies have, usefully, studied their own predecessors. Hindustan Zinc Limited has published work on the ancient workings at Zawar, Rajpura-Dariba and Rampura-Agucha; the copper mines at Khetri in Rajasthan preserve detailed evidence of ancient extraction technique. Nearly every major modern mining centre in India sits on or beside old workings — which is not a coincidence but a consequence: the ore bodies that outcrop and are easy to find were found early.

The scale is worth registering. Fifteen thousand tonnes of zinc, produced a retort at a time in a process that yields perhaps a few hundred grams per firing, implies an industry running continuously for centuries with an organised fuel supply, labour force and distribution network.

3Wootzवुट्ज्

A high-carbon crucible steel, made in India from at least the fourth century BCE, exported west, and forged in the eastern Mediterranean into the blades Europe called Damascus. It is the most famous single product of Indian technology, and the most instructive.

What makes wootz different from ordinary steel Bloomery iron is low carbon and worked solid; wootz is melted in a sealed crucible, reaching high carbon, and its carbides form the visible banding. ORDINARY BLOOMERY IRON Ore reduced with charcoal in a low furnace. The metal never melts — it forms a spongy “bloom” that must be hammered to drive out slag. Carbon content low and uneven. Soft, tough, and it is what most of the pre-modern world worked with. WOOTZ — CRUCIBLE STEEL Iron sealed in a clay crucible with a carbon source, held at high heat for hours. The metal melts, so carbon dissolves evenly through it. Carbon around 1.0–1.9% — far above what a bloomery reaches. Hard, and capable of a very fine edge. The banding — the visible signature On slow cooling, iron carbide (Fe₃C) segregates into sheets. Forging draws these out into the flowing bands seen on a finished blade. The pattern is not decoration applied to the surface — it is the internal structure of the metal, revealed by etching.
The Hindus excelled in the manufacture of iron, and it was impossible to find anything to surpass the edge of Indian steel.
Arab account, twelfth century CE

By the end of the seventeenth century, shipments of tens of thousands of wootz ingots were leaving the Coromandel coast for Persia. Michael Faraday — whose father was a blacksmith — spent several years from 1818 studying wootz with the cutler James Stodart, trying to work out what made it different. They did not succeed, and neither did anyone else in Europe until the twentieth century, when the answer turned out to depend on trace elements in particular Indian ores and on a cooling schedule nobody had recorded.

4Making itक्रिया

The process as recorded from working furnaces in south India. Note that the sequence is a carburising route, and that Europe did not have one until the eighteenth century.

The crucible steel process step by step Wrought iron is cut, packed into crucibles with leaves, sealed, fired under bellows for six hours, then quenched, yielding conical ingots. 1 · START FROM WROUGHT IRON Ore heated with charcoal in small blast furnaces gives wrought iron directly — low in carbon, not cast iron. Each piece is then cut into three parts, to fit the crucible. 2 · CHARGE THE CRUCIBLE Into each crucible go the iron pieces, a handful of dried taṅgeḍu twigs (Cassia auriculata) and fresh leaves of vonaṅgaḍi (Convolvulus laurifolia). Seal the mouth with red mud. 3 · FIRE Crucibles are set in a pit in a circle, bottoms toward the centre. The pit is filled with charcoal and large bellows are worked for six hours. The iron melts; the carbon dissolves in. 4 · WITHDRAW AND QUENCH The crucibles are taken from the fire and water is thrown on them while still hot. The steel is found as a conical cake at the bottom of each crucible — the wootz ingot, which is what was traded. Two routes to steel, and which one this is Steel can be made by removing carbon from cast iron, or by adding it to wrought iron. This is the second — carburisation. The leaves are the carbon source, and the seal keeps the atmosphere reducing so the carbon goes in rather than burning off.
Benjamin Huntsman's crucible steel process, developed in Sheffield in the 1740s, is recognisably this. The Indian version had been running for something like two thousand years.

5A classification of alloysलोहभेदाः

The Rasa-ratna-samuccaya divides iron into three classes and each class into named varieties, distinguished by properties a smith can test. Set the list beside a modern iron–carbon classification and the correspondence is striking.

The Rasa-ratna-samuccaya classification of iron Three classes: kanta-loha the soft magnetic irons, tiksna-loha the carbon steels, and munda-loha the cast irons, with named varieties in each. Kānta-lohaकान्तलोह SOFT IRON — sorted by magnetism ≈ modern wrought / low-carbon iron Bhrāmakavery soft, magnetic Cumbakamildly magnetic — sticks to iron pieces Karṣakaattracts iron objects Drāvakastrongly magnetic Romakaa permanent magnet — develops a field around itself The whole class is ordered by a single measurable property, graded from “barely magnetic” to “permanently magnetised”. Magnetic softness does in fact track low carbon content. Tīkṣṇa-lohaतीक्ष्णलोह “SHARP IRON” — sorted by edge and fracture ≈ modern carbon steel Kharatakes a good cutting edge, but breaks when bent Sārasofter; fibrous fracture Hṛnnālahard and tough; fibrous fracture Tārāvaṭṭatakes a good cutting edge Vājirahardens and tempers well; bluish; hard cutting edge Kāladevelops a hard edge after tempering The diagnostic here is the fracture surface — break a bar and look at the break. It is exactly what a nineteenth-century steelmaker did, and what fractography still does. Muṇḍa-lohaमुण्डलोह “BLUNT IRON” — sorted by casting behaviour ≈ modern cast iron Mṛdusoft, brittle, low melting point Kuṇṭhagrey iron Kadārawhite cast iron Grey and white cast iron are still the standard distinction — they differ in whether the carbon is graphite or cementite.
Three classes ordered by increasing carbon content, though the concept of carbon was of course unavailable. The classification is empirical throughout — magnetism, edge-holding, fracture appearance, melting behaviour — and it sorts the material correctly. This is what a mature craft taxonomy looks like: right about the phenomena, silent about the cause.

6Ranking the regional ironsयुक्तिकल्पतरुः

The Yukti-kalpataru (11th century CE) grades the irons of different regions against one another, with multipliers:

सामान्याद् द्विगुणञ्चोक्तं कलिर्दशगुणस्ततः । कलेः शतगुणं भद्रं भद्राद्वज्रं सहस्रधा ॥
वज्रात् षष्टिगुणः पाण्डिर्निरविर्दशभिर्गुणैः । ततः कोटिसहस्रेण ह्ययस्कान्तः प्रशस्यते ॥

Yukti-kalpataru 85.31–32

A ranking of regional irons with multipliers Each grade is a stated multiple of the one before, running from ordinary iron up to lodestone. Sāmānya ordinary ×2 Krauñca ×10 Kaliṅga Odisha ×100 Bhadra ×1000 Vajra “diamond” ×6 Pāṇḍi ×10 Niravi × ten billion Kānta / ayaskānta the lodestone Read the numbers as rhetoric, not as measurement — “ten billion times better” is a way of saying “in a different category altogether”, and the item so praised is magnetic iron, valued for reasons other than cutting. What is substantive: iron from different regions was recognised as differing in quality, the differences were consistent enough to be ranked, and the ranking was worth writing down. Ore chemistry varies by deposit, and trace elements matter — so a regional ranking is a real, if crude, materials science.
A good example of how to read a technical text: strip the hyperbole and the informational content survives intact.

7The pillars and beamsलोहस्तम्भाः

Large forge-welded iron objects, made without a blast furnace, several of which are still standing.

The great iron objects and why the Delhi pillar does not rust The Delhi, Dhar and Mount Abu pillars and the Konark beams, with an explanation of the passive phosphate layer. Delhi — the Mehrauli pillar c. 400 CE · about 7.2 m · roughly 6,000 kg Standing in the open air for sixteen centuries with only superficial corrosion. Dhar, Madhya Pradesh 12th century CE · roughly 7,000 kg — larger than the Delhi pillar, though now broken in pieces. Mount Abu A third such pillar. Konark, Odisha Twenty-nine iron beams in the Sun Temple, some of them buried in sea sand for centuries and recovered intact. 239 more pieces at the Gundicha temple in Puri, and others at Bhubaneswar. Why the Delhi pillar does not rust The iron is unusually high in phosphorus — around 1%, where modern steels keep it below 0.05% because it causes brittleness. In humid air, that phosphorus produces a thin, dense, adherent layer of hydrated iron oxide-hydroxide that seals the surface instead of flaking off. Where the phosphorus came from Not by design. A bloomery process using charcoal and no limestone flux leaves the phosphorus in the metal; a modern blast furnace removes it into the slag. So the corrosion resistance is a by-product of the process rather than an intended alloy design — which does not make the forge-welding of six tonnes of iron by hammer any less remarkable.
Two claims to keep separate. That the pillar resists corrosion, and that the mechanism is a phosphorus-derived passive film, are both established by metallurgical analysis. That the makers understood and intended this is not established, and the more likely story is that a process which happened to retain phosphorus was used for centuries and its products observed to last.

The cannons of the medieval period make the same point about scale. Large forge-welded iron guns survive at Nurwar, Murshidabad, Dhaka, Bishnupur, Bijapur, Gulbarga and Thanjavur. Making a barrel that will not burst, by welding staves and hoops together under a hammer, is a serious problem in both metallurgy and engineering.

8Surgical steelशस्त्राणि

The most exacting demand on a pre-modern steel is not a sword. It is a scalpel.

The Suśruta-saṃhitā describes more than a hundred surgical instruments in iron–carbon alloy, together with the heat treatment needed to obtain their edges. Its stated test for sharpness is that the blade should split a hair longitudinally.

Categories of surgical instrument described by Susruta Cutting, piercing, extracting, probing and cauterising instruments, plus the sharpness test. chedana excising, cutting bhedana · vedhana splitting, puncturing āharaṇa forceps, extractors eṣaṇa probes, sounds dahana cautery Why this is a metallurgical claim as much as a medical one An instrument that must take that edge, hold it through a procedure, be re-sharpened and be heated for sterilisation needs a specific carbon content and a controlled quench-and-temper cycle. A hundred such instruments implies not a lucky batch but a repeatable process — and a specification a smith could be held to. Chapter 13 returns to what these were used for.

9Zinc, and why it is hardयशदम्

Zinc is the strongest single claim in this chapter, because the difficulty is a matter of physical chemistry and can be stated exactly.

Why zinc cannot be smelted like other metals, and the downward distillation solution A temperature scale showing that zinc boils below the reduction temperature, so the metal leaves the furnace as vapour and must be condensed away from air; and the retort arrangement that achieves it. THE PROBLEM, ON A TEMPERATURE SCALE 400 °C600 °C800 °C1000 °C1200 °C 419 °C — zinc melts 907 °C — zinc boils ≈ 550 °C — in open air, zinc re-oxidises to ZnO ≈ 1000 °C and above — the temperature at which carbon will reduce ZnO to the metal The bind You must reach about 1000 °C to reduce the ore. But zinc boils at 907 °C. So the instant the metal forms, it is a vapour. Let that vapour meet air on the way out and it burns straight back to zinc oxide — which is what you started with. This is why zinc, unlike copper, tin, lead, silver, gold or iron, cannot be smelted by simply heating ore with charcoal and pouring off the metal. Every other ancient metal can. The solution — downward distillation Seal the ore and charcoal in a retort. Point the retort's neck downwards, into a cool receiver below the fire. The vapour, denser than air and driven by its own pressure, travels down out of the hot zone and condenses to liquid metal below about 500 °C — where it can no longer burn. Downwards, not upwards, is the whole trick: it uses gravity to carry the product away from the heat and the air at once.
The Zawar zinc retort arrangement Rows of brinjal-shaped retorts set over perforated plates in a furnace, with condensers hanging beneath. the fire chamber — charcoal, forced draught Retorts charged with ore + charcoal, sealed, each with a downward tube. perforated plate The cool chamber below. Vapour descends, condenses, and collects as liquid zinc. Tens of thousands of spent retorts remain on the ground at Zawar. The Rasa-ratna-samuccaya describes a yantra for exactly this operation.
The archaeology at Zawar shows this arrangement operating at something close to industrial scale by the mid-fourteenth century — banks of retorts fired together, in a repeated cycle. India appears to have been the first place to produce metallic zinc, from somewhere between 600 and 200 BCE, and was exporting it before the eleventh century CE.

10Copper and brassताम्रम् · पित्तलम्

Copper was in heavy use long before zinc, and the objects are large. A copper Buddha found at Sultanganj, Bihar, stands about seven and a half feet and weighs a tonne. Xuanzang reports seeing a brass image some eighty feet high near Nālandā, in a vihāra built by King Śīlāditya (606–647 CE). Copper's steadiest use, though, was coinage.

Brass is where the zinc story pays off. There are two routes:

Cementation

Heat copper with zinc ore (calamine) and charcoal. Zinc vapour is absorbed directly into the solid copper. Xuanzang records Indians making brass from copper and calamine this way.

Limit: the process saturates at roughly 28% zinc. It cannot go higher.

Direct alloying

Melt copper and add metallic zinc. Any composition is then reachable.

The evidence: the brass vase from Taxila (4th century BCE) assays at 34.34% zinc — above the cementation ceiling. It could only have been made by adding zinc metal, which means zinc metal existed.

Why that single number matters

A composition figure is doing serious argumentative work here. Cementation has a hard chemical ceiling; 34% is above it; therefore metallic zinc was available in India in the fourth century BCE. This is an inference from a measurement to a technology, of exactly the kind that makes archaeometallurgy worth doing — and it does not depend on any text saying so.

Dated brass objects — the chronology of an alloy
Date and siteObject
c. 1500 BCE, LothalCopper object no. 4189
Harappan, RojdiChisel, celt rod, bangle
4th c. BCE, TaxilaThe vase — 34.34% zinc
2nd c. BCE, TaxilaBangle
2nd c. CE, GujaratIndo-Parthian female figure with flower container
5th c. CE, GandhāraBuddha
6th c. CE, AkotaAmbikā
7th c. CE, MahudiṚṣabhanātha
8th c. CE, KashmirŚiva
9th c. CE, NālandāBuddha
11th c. CE, western TibetMañjuśrī
1350 CE, GujaratAmbikā
c. 1480 CEModel temple with four doors, 10 × 24.5 cm
c. 1485 CEViṣṇu-Nārāyaṇa
15th–16th c. CE, RajasthanRajput prince on horseback
1554 CE, GujaratKāla Bhairava

11Goldसुवर्णम्

Gold extraction in India has been studied and documented by Bharat Gold Mines from the ancient workings at Kolar. Refined gold went to three places: ornament, worked by forging, punching and embossing into designs of great intricacy — the first-century BCE royal earrings from Andhra Pradesh are the standard example; coinage, either die-cast in clay moulds or struck by punch-marking; and medicine, as svarṇa-bhasma, a calcined gold preparation used in Āyurveda (chapter 13).

That third use is worth noticing here for a technical reason. Producing a bhasma requires reducing a metal to an extremely fine, chemically altered powder by repeated cycles of grinding and calcination — dozens of firings, in some prescriptions hundreds. Whatever one concludes about its medical value, it is a demanding materials process, and it is why the Āyurvedic and alchemical traditions became sophisticated metallurgists in their own right.

12Lost-wax castingमधूच्छिष्टविधानम्

The technique behind the Chola bronzes, and behind the dancing girl of Mohenjo-daro some three thousand years earlier. Its Sanskrit name is exact: madhūcchiṣṭa-vidhāna, “the method of what is left over from honey” — that is, beeswax.

The five stages of lost-wax casting A wax model is coated in clay slurry, the wax is baked out, metal is poured in, and the mould is broken away. 1 · THE WAX The figure is modelled in beeswax, in full detail. 2 · THE SHELL Coated in clay slurry — clay, charred rice husk, and salt — in fine layers. 3 · BURN OUT The shell is baked; the wax runs out, leaving a hollow of exactly its shape. 4 · POUR The shell is packed in a sand-clay box for support and the metal poured in. 5 · BREAK OUT The mould is destroyed to free the casting, then filed, chiselled and polished. The consequence that defines the technique Both the wax model and the mould are destroyed in making a single casting. Every lost-wax bronze is therefore unique — there is no reusable pattern and no second copy. That is why Chola bronzes are individual works rather than editions, and why the sculptor's labour is spent on the wax, which nobody will ever see.

The literary record

  • Viṣṇu-saṃhitā, chapter 14 (5th c. CE): a wax model must be made before the metal replica.
  • Mānasāra, chapter 68: full details of madhūcchiṣṭa-vidhāna.
  • Mānasollāsa and Abhilaṣitārtha-cintāmaṇi (12th c.): preparation of the wax pattern and the slurry coating, with the recipe — clay, finely ground charred rice husk, and sodium chloride.

The husk burns out during firing, leaving porosity that lets gas escape during the pour; the salt affects the slurry's working properties. Both are functional additions, not filler.

Pañca-loha

पञ्चलोह

Icons are often cast not in bronze but in an alloy of five metals — conventionally gold, silver, copper, zinc and iron, though the list varies by text and region.

The practice has an obvious symbolic reading, and also a metallurgical one: the additions change the melting range and fluidity of the melt, which matters when filling a thin-walled mould with fine detail.

The technique is not extinct. The dhokra work of the Bastar region is lost-wax casting still being practised, in brass and bronze, by communities who learned it as a craft rather than from a text.

13The laboratoryरसशाला

Three distinct communities extracted metals in India, at three different scales, and their apparatus is best documented by the smallest of them.

Three communities working with metals Metalworking engineers at industrial scale, Ayurvedic practitioners preparing bhasmas, and alchemists. Metalworking engineers Mine the ore, run the furnaces, cast and forge the product. By far the largest scale — the Zawar retort banks, the pillars, the wootz trade, the coinage. Left the most archaeology and the least writing. Āyurvedic practitioners Extract metals and reduce them to bhasmas — calcined powders for therapeutic use. Small quantities, but demanding purity and repeatability — which is why they documented apparatus and procedure so carefully. Alchemists · rasa-śāstra Extract and transform metals for alchemical ends — mercury above all. Nāgārjuna's Rasaratnākara (1st c. CE) is the early landmark. The aims were not achievable; the techniques — distillation, sublimation, calcination — were real and were inherited by everyone else.
51kinds of tool (upakaraṇa)
36kinds of apparatus (yantra)
17types of crucible (mūṣā)
9types of furnace (pūṭa)

as catalogued in the Rasa-ratna-samuccaya

Two apparatus from the Rasa-ratna-samuccaya The dola-yantra suspends material in cloth inside a liquid; the patana-yantra condenses vapour into a second cooled vessel. Dolā-yantra — the swing दोलायन्त्रम् The material is tied in cloth, suspended from a rod, and hung in a pot half-filled with the treating liquid. A steady bath, without contact with the vessel. Pātana-yantra — the descender पातनयन्त्रम् heated cooled For sublimation and distillation. Vapour passes through a tube into a second pot, kept cool with water, where it condenses and collects. This is the zinc problem of §9, generalised into a standard piece of laboratory glassware.
An apparatus catalogue running to well over a hundred items, with each device named, described and assigned to particular operations, is the signature of a laboratory tradition — one in which procedures were expected to be reproduced by someone else, somewhere else.

14The rise and the fallउत्थानपतनम्

Timeline of Indian steel production and its decline From production before 700 BCE through the export peak of the seventeenth century to the collapse under colonial taxation and mining bans. c. 700 BCE wootz produced inseveral Indian regions to 12th c. CE exported through the Arab world;forged into Damascus blades 17th c. CE tens of thousands of ingots shippedyearly from the Coromandel coast 1818–1820s Faraday and Stodart study wootzin London — and fail to reproduce it 19th c. CE production taxes andmining bans under the Raj The end was not technical. The process still worked; the market still existed; the ore was still in the ground. What changed was the policy environment — and a craft of hundreds of small dispersed furnaces cannot survive its supply being cut.
How to state the decline fairly

Colonial-era taxation and restrictions on mining and charcoal are documented, and they hurt. But a full account has to include other factors: the arrival of cheap imported wrought iron and later Bessemer steel, which undercut a labour-intensive craft on price; deforestation, which raised the cost of charcoal independently of policy; and the fact that crucible steel was, by 1850, a technology Europe had reinvented at scale. Attributing the collapse to a single cause is neither accurate nor necessary — the documented policy effects are damaging enough on their own.

15Self-checkपरीक्षा

Check your reading

1 · What distinguishes wootz from ordinary bloomery iron?

Melting is the key. The banding is the internal carbide structure of a high-carbon melt, revealed by etching — not a surface treatment and not a consequence of folding.

2 · Why can zinc not be smelted the way copper or lead is?

Hence downward distillation: point the retort's neck down so gravity carries the vapour out of the heat and away from the air, to condense below 500 °C.

3 · Why does a Taxila vase assaying 34.34% zinc matter?

An inference from a measurement to a technology, independent of any text.

4 · What is the correct account of the Delhi pillar's corrosion resistance?

Both the resistance and the mechanism are established. Intent is not, and does not need to be claimed — forge-welding six tonnes of iron by hand is impressive without it.

5 · Why is every lost-wax bronze unique?

Which is also why the sculptor's whole effort goes into a wax figure that nobody will ever see.

Questions worth arguing about

How much can be inferred from an object about the knowledge of its makers?

Less than one would like, and the pillar is the cautionary case. An object proves that a process was executed; it does not prove that the executors held a theory of why it worked. Craft knowledge is often entirely procedural — do this, in this order, at this colour of heat — and can produce excellent results with no explanatory account at all. Insisting on theory before granting achievement is a mistake; so is reading theory back out of achievement.

Was the Rasa-ratna-samuccaya's classification of iron “scientific”?

It has the shape of a science: mutually exclusive classes, named varieties, diagnostic tests, and a correct ordering. It lacks a causal account — there is no carbon, so nothing explains why the classes differ. Whether one calls that a science or a mature craft taxonomy is partly terminological, but the more useful question is what it enabled: a smith could specify what he needed and be understood, which is what a technical vocabulary is for.

What would it take to revive a lost process like wootz?

Modern work has come close, and the difficulties are instructive: the ore's trace elements matter (vanadium and molybdenum at parts-per-million levels appear to nucleate the carbide bands), the cooling rate matters, and the forging schedule matters. None of these was written down, because none of them was known — they were embodied in a place, a practice and a set of hands. That is exactly the category of knowledge chapter 1 identified as most at risk.

16Glossaryशब्दकोशः

IASTDevanāgarīSense
ayaskāntaअयस्कान्तLodestone; magnetic iron ore.
bhasmaभस्मA calcined metallic preparation used medicinally.
kānta-lohaकान्तलोहThe class of soft magnetic irons.
madhūcchiṣṭa-vidhānaमधूच्छिष्टविधान“The method of beeswax”: lost-wax casting.
muṇḍa-lohaमुण्डलोहThe class of cast irons.
mūṣāमूषाA crucible.
pañca-lohaपञ्चलोहAn alloy of five metals, used for icons.
pātana-yantraपातनयन्त्रA distillation or sublimation apparatus.
pittalaपित्तलBrass.
rasa-śāstraरसशास्त्रThe science of mercury and metallic preparations; Indian alchemy.
tāmraताम्रCopper.
tīkṣṇa-lohaतीक्ष्णलोह“Sharp iron”: the class of carbon steels.
upakaraṇa / yantraउपकरण / यन्त्रA tool; an apparatus or machine.
yaśadaयशदZinc.
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