What is ruby? Corundum, chromium, and the world's most valued red stone

Corundum: the mineral species that produces ruby and sapphire

Ruby and sapphire are the same mineral species. Both are corundum: aluminium oxide with the chemical formula Al₂O₃. In its pure form, corundum is colourless. What makes one corundum crystal red and another blue, or yellow, or purple, or orange, is entirely a matter of which trace elements are present and in what combination.

Corundum belongs to the trigonal crystal system, which means its atoms are arranged in a hexagonal close-packed structure with three-fold rotational symmetry. The aluminium atoms sit in octahedral sites surrounded by six oxygen atoms. It is into these octahedral sites that chromium, iron, titanium, and other transition metals substitute at trace levels to produce colour. The host structure, the oxygen and aluminium framework, is itself colourless. The colour chemistry happens entirely through the substituted impurities (Klein, C., Manual of Mineral Science, 22nd ed., Wiley, 2002, p. 286; GIA Gem Reference Guide, 2006, p. 40).

Corundum has a Mohs hardness of 9, making it the second hardest natural mineral after diamond (10). This hardness gives ruby and sapphire exceptional durability for jewellery use: corundum will not be scratched by household dust or quartz particles, which measure 7 on Mohs. Corundum has no cleavage (it does not break along preferred crystal planes), though it has three directions of parting along twin planes, which can cause splitting under certain impacts. The lack of true cleavage makes ruby a more durable gem than diamond in some respects, since there is no plane along which a sharp blow will predictably split it (GIA Gem Reference Guide, 2006, p. 40; Deer, Howie, and Zussman, Rock-Forming Minerals, 2nd ed., 1997, Chapter on oxides).

The refractive index of corundum is 1.762 to 1.770, depending on orientation (corundum is doubly refractive, with different RI values measured along different crystal axes). The birefringence, the difference between the two RI values, is approximately 0.008. This double refraction is visible under magnification as doubling of back facets when the stone is viewed from certain angles. The relatively high RI contributes to corundum's brilliance, though ruby's colour saturation is typically the dominant visual feature rather than light return in the way it is for colourless diamonds (GIA Gem Reference Guide, 2006, pp. 40–41).

How corundum forms in the earth

Gem-quality ruby forms in two principal geological environments, and the environment shapes the stone's chemistry and therefore its appearance. Understanding these environments explains why Burmese ruby from Mogok looks and behaves differently from Thai ruby from Chanthaburi, or Mozambican ruby from Montepuez, and why origin matters so much in this market.

Marble-hosted ruby forms when aluminium-rich solutions penetrate metamorphosed limestone (marble) during regional metamorphism. The marble environment is critical because marble is very low in iron. Iron suppresses chromium fluorescence in corundum: when iron is present at significant levels, it quenches the fluorescence that chromium would otherwise produce. Marble-hosted rubies from Mogok in Myanmar, from Mong Hsu (also Myanmar), from Jegdalek in Afghanistan, and from certain localities in Tajikistan form in low-iron environments and tend to fluoresce strongly under UV and in sunlight. The result is that luminous, internally lit quality that the trade calls "alive" and that commands the highest premiums in the ruby market (Hughes, R.W., Ruby and Sapphire, 1997, pp. 100–120; Gübelin, E.J. and Koivula, J.I., Photoatlas of Inclusions in Gemstones, ABC Edition, Zurich, 1986, Vol. 1).

Basalt-hosted ruby forms in alkali basalt volcanic rocks, where iron-rich geological conditions produce corundum with significantly higher iron content. Thai rubies from Chanthaburi-Trat, Cambodian rubies from Pailin, Australian rubies from New South Wales, and some Vietnamese rubies form in basalt-related environments. The higher iron content suppresses fluorescence and produces stones that are darker, more strongly red without the purplish secondary hue of Mogok stones, and notably less luminous. Basalt-hosted rubies are often strongly heated to improve their colour by reducing the blue tone that iron can cause, and the market treats them differently from marble-hosted stones (Hughes, 1997, pp. 120–135; Wise, R.W., Secrets of the Gem Trade, 2nd ed., Brunswick House Press, 2016, pp. 70–80).

Chromium: what it does inside a ruby crystal

Chromium is the element that makes ruby red, but the mechanism is more interesting than simple colour absorption, and understanding it explains observations that would otherwise be puzzling: why ruby glows in sunlight, why Burmese rubies glow more than Thai rubies, and why chromium produces green in emerald but red in ruby.

Crystal field theory and the colour of ruby

When a chromium ion (Cr³⁺) is placed in the octahedral aluminium site in the corundum crystal structure, it experiences a crystal field: an electric field produced by the six surrounding oxygen atoms at the corners of the octahedron. This field splits the energy levels of chromium's 3d electrons into two groups. Transitions between these energy levels correspond to specific wavelengths of light. The crystal field in corundum forces chromium to absorb strongly in the blue-violet region (around 400–420 nm) and in the yellow-green region (around 550–600 nm), and to transmit red wavelengths at the high end of the visible spectrum (around 630–700 nm). The result is a stone that appears red to the eye (Fritsch, E. and Rossman, G.R., "An Update on Color in Gems, Part 1," Gems and Gemology, 24(2):81–102, 1988; Nassau, K., "The Origins of Color in Minerals," American Mineralogist, 63:219–229, 1978).

Emerald also contains chromium as its primary chromophore. Both ruby and emerald owe their colour to Cr³⁺. Yet ruby is red and emerald is green. The difference is entirely in the crystal field: beryl's crystal structure places chromium in a slightly different geometric environment from corundum's, producing a different crystal field strength. This shifts the absorption bands differently, and emerald transmits green rather than red. The same element produces opposite colours in different host minerals because the surrounding crystal structure determines which wavelengths are absorbed (Fritsch and Rossman, 1988, op. cit., p. 88). This is one of the most elegant demonstrations in gemological science.

Chromium concentration and colour saturation

The concentration of chromium in ruby affects both colour intensity and fluorescence intensity. At very low concentrations (below roughly 0.1 percent by weight), the stone appears pale pink, with insufficient chromium to saturate the colour. At optimal concentrations (roughly 0.5 to 1.5 percent), the stone shows vivid red with strong fluorescence. At high concentrations (above approximately 2–3 percent), the stone may become so darkly saturated that face-up colour approaches brownish-red. The finest Mogok rubies sit in the optimal range, with sufficient chromium for vivid saturation but not so much that the colour darkens excessively. The precise chromium content of a specific stone is measured by laboratories using LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) and contributes to origin determination reports, because different deposits have characteristic trace element profiles (GIA Colored Stone Department; Gübelin Gem Lab technical notes; Lotus Gemology, Hughes and Pardieu, lotusgemology.com).

Fluorescence: why ruby glows in sunlight

Ruby's fluorescence is among the most commercially significant optical properties of any gemstone, and it is a property that most buyers never hear explained. It is the physical reason that a fine Burmese ruby looks alive in a way that an equivalent Thai or Mozambican ruby may not.

What fluorescence is and why ruby has it

Fluorescence is the emission of visible light by a material when it absorbs radiation at a shorter wavelength. In ruby, chromium absorbs ultraviolet radiation (wavelengths below the visible spectrum) and re-emits some of that energy as red light. Natural daylight contains significant UV: at sea level on an overcast day, sunlight still contains substantial ultraviolet radiation across the UV-A range (315–400 nm). When this UV hits a ruby, chromium absorbs it and emits red photons in return. These additional red photons add to the stone's face-up appearance, increasing apparent colour saturation and creating the "glow from within" quality that the trade values (Nassau, K., Gems Made by Man, Chilton Book Company, 1980, Chapter 3; Fritsch and Rossman, 1988, op. cit.).

Under a UV lamp in a darkened room, fine Burmese rubies glow with a vivid red fluorescence that is immediately obvious. The same effect, at lower intensity, operates in natural daylight. This is not metaphor: the stone is literally emitting light in response to UV absorption, in addition to transmitting and reflecting visible red light. No amount of artificial illumination engineering fully replaces this effect: a ruby that glows under sunlight can look slightly less exceptional under LED or fluorescent lighting that lacks UV.

Why Burmese rubies fluoresce more strongly

The key to understanding differential fluorescence is iron. Iron (Fe²⁺ and Fe³⁺) in corundum quenches chromium fluorescence through a process called energy transfer. When iron is present alongside chromium, the excited chromium ions transfer some of their energy to nearby iron ions rather than emitting it as light. The more iron, the more quenching, the weaker the fluorescence.

Marble-hosted rubies from Mogok form in an iron-poor geological environment. Iron content in these stones is typically very low, often below detection limits for common analytical techniques. Basalt-hosted rubies from Thailand, Cambodia, and Australia form in iron-rich environments and contain significantly more iron. The iron does not produce visible colour at the concentrations typically found, but it efficiently quenches chromium's fluorescence. The result: a Mogok ruby with identical chromium content to a Thai ruby of equivalent colour will appear more luminous and vivid in daylight, because iron is not suppressing its fluorescence (Hughes, R.W., Ruby and Sapphire, 2017 updated edition, Lotus Gemology, Chapter on Mogok; Wise, 2016, pp. 72–75).

This is a measurable, verifiable physical difference. Gemological laboratories measure iron content as part of their origin determination analysis. "Low iron" is not just a description of Mogok character: it is a quantitative statement with a price implication. An unheated Mogok ruby with low iron and strong fluorescence is genuinely optically different from a heated Thai ruby of comparable colour grade. The market prices that difference at a premium that can be substantial (Christie's Geneva, Sotheby's New York, published auction results 2015–2025).

Iron quenches chromium fluorescence in ruby by intercepting the energy transfer before red light can be emitted. Marble-hosted rubies (Mogok, Myanmar) have low iron and strong fluorescence. Basalt-hosted rubies (Thailand, Cambodia) have high iron and weak fluorescence. Source: Hughes (1997); Fritsch and Rossman (1988).

The ruby vs pink sapphire boundary: where science ends and commerce begins

Both ruby and pink sapphire are the mineral species corundum. Both are coloured by chromium. Both occupy the red-to-pink colour range. The boundary between them is not defined by physics or chemistry. It is defined by trade convention, and different bodies draw it differently.

The commercial history of the distinction

The ruby versus pink sapphire distinction matters commercially because the names carry different price expectations. "Ruby" implies the prestige of the most valued coloured gemstone. "Pink sapphire" implies a paler, less rare variant of sapphire. A stone on the boundary that is called a ruby can sell for significantly more than the same stone called a pink sapphire. This price gap gives dealers an incentive to push marginal stones toward the ruby classification, and it gives laboratories a responsibility to apply consistent standards.

Historically, trade practice in many countries drew the boundary at the point where red becomes the dominant visible colour to the eye. A stone with primary hue red, even with pink secondary hue, was a ruby. A stone with primary hue pink was a pink sapphire. GIA's grading system introduced a more specific framework using the hue, tone, and saturation model: under GIA's approach, a stone must have red as its primary hue (not pink) to qualify as ruby. The tone must be sufficient to show red rather than just pink. And the saturation must reach a minimum threshold (GIA Gem Reference Guide, 2006, pp. 40–43).

Where GIA and other labs draw the line

GIA's position is that corundum with red as the dominant hue and sufficient saturation to be called red, rather than pink, qualifies as ruby. Corundum where pink is the dominant hue is pink sapphire. The difficulty is that "red versus pink" is a spectral continuum without a natural boundary, and observers do not agree on where red ends and pink begins. GIA uses trained graders applying defined saturation thresholds, but the boundary zone between approximately 3 and 5 on the GIA saturation scale produces genuine ambiguity (GIA Colored Stone grading documentation; GIA Gem Reference Guide, 2006, p. 42).

The Thai trade and some international dealers historically used a broader ruby definition that included stones GIA might call pink sapphire. The Burmese trade in Mogok has always considered any chromium-coloured corundum from its valley to be ruby regardless of the degree of pinkness, because the cultural and commercial identity of Mogok is built around ruby. The AGL (American Gemological Laboratories) and Gübelin Gem Lab apply standards that broadly align with GIA's framework but acknowledge that stones near the boundary require judgment (AGL treatment nomenclature; Gübelin technical notes; Hughes, 1997, pp. 80–95).

For buyers, the practical implication is this: a laboratory report that says "ruby" is telling you the classifying lab's grader determined the stone's hue and saturation qualify as ruby under their standard. A report that says "pink sapphire" is telling you the same. A stone without a report, described as ruby by a seller, may or may not meet any lab's standard. For fine stones above approximately Rs 2 lakh per carat, a GIA, Gübelin, or AGL report with species identification and treatment status is the only reliable basis for purchase.

Quality factors in ruby: what determines value

Ruby is evaluated across the same four quality dimensions as all coloured gemstones: colour, clarity, cut, and carat weight. But the weighting of these factors is different from diamonds, and the treatment status operates as an additional quality tier that cuts across all four dimensions.

Colour: the dominant factor by far

Colour is the primary value driver in ruby to a degree that exceeds almost any other gemstone. A fine colour ruby with inclusions visible to the eye will sell for more than a flawless ruby with mediocre colour. This is a principle stated consistently by major dealers and documented in auction results: the finest rubies reach their prices because of colour, not clarity or cut (Wise, R.W., Secrets of the Gem Trade, 2nd ed., 2016, pp. 70–90; Hughes, 1997, pp. 80–100).

The colour description for the finest rubies has historically used the term "pigeon blood," a trade term for a specific quality of red associated with the finest Burmese stones. The Gübelin Gem Lab, AGL, and SSEF use this term in certificates with precise technical meaning: a pure red hue with slight purplish secondary hue, medium-dark tone (typically 6 to 7 on the GIA scale), and vivid saturation, with the stone also showing fluorescence that enhances face-up colour in daylight. Not all of these laboratories apply the term identically, and it should be used in trade contexts only when attributed to a specific laboratory report that employs the designation (Gübelin Gem Lab; AGL technical notes; SSEF technical notes). The Gemstone Codex uses "pigeon blood" only in this context.

The GIA colour description framework for ruby (as for all coloured stones) uses hue, tone, and saturation. The optimal ruby has:

Hue: Primary hue red (R), with a secondary hue of slightly purplish (slightly purple-red, or "PR") that enhances the impression of redness through what Hughes calls the "pigeon blood" effect. A strongly orangey red ("OR") is less desirable, though orange-red stones (sometimes called "fire rubies" in trade) can be quite beautiful. A strongly purplish red ("PR" at the extreme end) moves toward the garnet or purple sapphire territory and is less commercially desirable as ruby.

Tone: Medium-dark, typically tone 6 or 7 on the GIA 0–10 scale. Too light (tone 3–4) produces pink sapphire character. Too dark (tone 8–9) produces a brownish-red that loses the luminosity of the finest rubies.

Saturation: Vivid or strong, meaning the colour is pure and intense with minimal grey or brown modifier. A greyish-red or brownish-red ruby, even at correct tone and hue, is significantly less valuable than a vividly saturated stone. This is the quality that separates a commercial Mozambican ruby from a fine unheated Burmese ruby of equivalent size: the Burmese stone at its best shows vivid saturation without grey or brown modification (GIA Gem Reference Guide, 2006, pp. 40–43; GIA Colored Stone Grading System documentation).

Clarity: Type II and what it means for ruby

Ruby is classified as a Type II gemstone in GIA's clarity type system, meaning that inclusions are a normal, expected feature of the species. Gem-quality rubies almost always contain inclusions visible under magnification, and many contain inclusions visible to the naked eye. This is not a defect in the same way that a flawless diamond's clarity grade represents a quality extreme: for ruby, eye-clean clarity is exceptional, not expected (GIA Gem Reference Guide, 2006, pp. 28–30).

The most common inclusions in ruby are rutile needles (producing the silk effect), calcite and other mineral crystals from the host rock (especially in marble-hosted Mogok rubies), negative crystals (small voids with the shape of the corundum crystal), and fingerprint inclusions (networks of healed fractures containing fluid). These inclusions are part of the stone's natural character and, in the case of oriented rutile silk, can enhance the stone's appearance by diffusing light slightly and giving the stone a softer, glowing quality (Gübelin and Koivula, Photoatlas of Inclusions, 1986).

What reduces value in ruby clarity is: inclusions that break the surface (they weaken the stone and serve as entry points for treatments); fractures that significantly affect transparency or structural integrity; inclusions in the centre of the stone that interrupt the face-up colour; and heavy silk that reduces transparency to an unacceptable degree. A ruby that is heavily fractured and has subsequently been filled with lead glass is technically a "clarity-enhanced" stone, but "clarity-enhanced" is a significant understatement for what lead glass filling does: it fundamentally alters the stone's durability, stability, and resale characteristics. Lead glass rubies are covered in full detail in the companion article gems/treatments/lead-glass-ruby.html.

Type II clarity and silk: what makes ruby different from diamond

The Type II clarity classification places ruby, sapphire, alexandrite, and some other gem species in a category where inclusions are expected. This matters practically for buyers who come to coloured stones from a diamond background, where FL (flawless) to VS2 (very slightly included) represent the commercially acceptable range for quality diamonds, and SI1 or SI2 inclusions are visible under magnification.

In ruby, a stone that would receive an SI1 clarity grade in the diamond framework (inclusions visible under 10× magnification, eye-clean face-up) is considered fine clarity for its species. An eye-clean ruby, meaning no inclusions visible to the unaided eye in face-up viewing, is exceptional. An SI2-equivalent ruby, where inclusions are just visible to the naked eye, is commercially standard rather than a compromise. This does not mean clarity is irrelevant: inclusions that significantly reduce transparency, affect structural integrity, or catch the eye in face-up viewing reduce value significantly. It means the baseline expectation is different from diamonds (GIA Gem Reference Guide, 2006, pp. 28–30).

Silk and its optical effects

Rutile silk in ruby is among the most interesting inclusion phenomena in gemology. Rutile (titanium dioxide) grows as oriented needle-like crystals within the corundum crystal during formation, aligned along specific crystallographic directions in the trigonal crystal system. In corundum, rutile needles align in three directions at 60-degree angles to each other, producing the six-rayed asterism (star effect) when the stone is cut as a cabochon perpendicular to the c-axis. When the stone is faceted, the silk creates a subtle diffusion of light that gives fine rubies (and Kashmir sapphires, which have similar silk) a softer, more "glowing" appearance than silk-free stones (Gübelin and Koivula, 1986, Photoatlas, Vol. 1; Hughes, 1997, pp. 82–86).

Silk also plays a critical role in heat treatment detection. When ruby is heated above approximately 1,600°C (the temperature used in most commercial heat treatment), the fine rutile needles dissolve back into the corundum crystal lattice. After heating, the silk is absent or greatly reduced, and instead diffuse halo-like features called "rutile discoids" form around crystal inclusions as the rutile re-precipitates around solid inclusions during cooling. A trained gemologist examining a ruby under a microscope can often distinguish between a stone that has been heated and one that has not by the state of the silk: unheated stones show intact, sharp rutile needles; heated stones show absent or dissolved silk, often with rutile discoids. This is one of the primary diagnostic tools for heat treatment detection in ruby (Gübelin and Koivula, 1986; GIA Gems and Gemology journal; Gübelin Gem Lab technical notes).

Heat treatment and lead glass: the treatment landscape for ruby

The vast majority of commercial rubies have been heat treated. This is not a scandal or a fraud: heat treatment of ruby and sapphire is a long-established, universally disclosed practice in the gem trade. The treatment improves colour and reduces the appearance of silk inclusions. AGTA, ICA, and CIBJO all require disclosure of heat treatment, and all major gemological laboratories detect and report it on certificates (AGTA treatment disclosure codes; CIBJO Coloured Stone Blue Book; GIA Colored Stone reporting standards).

What matters for buyers is understanding the treatment hierarchy: at the top, unheated rubies command premiums that can be 2 to 10 times (or more, for exceptional stones) the price of comparable heated rubies. In the middle, heated rubies that have undergone only heat treatment (no fracture filling) are standard commercial goods, priced accordingly. At the bottom, rubies treated with lead glass filling represent a different category entirely: they require special care, are not stable under normal jewellery conditions, and are sold at prices far below heat-treated-only rubies.

Heat treatment operates by: dissolving or reducing silk inclusions; dissolving or reducing small fractures (a process called "healing"); adjusting colour by altering the oxidation state of iron and other trace elements. The temperatures used (typically 1,600–1,850°C in reducing or oxidising atmospheres) are below the melting point of corundum (approximately 2,044°C) but sufficient to cause significant atomic diffusion. After treatment, the stone is chemically still corundum with chromium, but its inclusion population and colour may be significantly different from the unheated original (GIA Colored Stone reporting; SSEF technical notes on heat treatment in corundum).

Lead glass filling is a separate, more significant treatment applied to rubies that are heavily fractured and would otherwise be unmarketable. Molten lead glass (a material with high refractive index, close to corundum's RI of 1.76–1.77, specifically chosen to be nearly invisible inside the fractures) is introduced into the stone's fractures at high temperature. The result is a stone that looks far more transparent and apparently of higher clarity than the unheated, unfilled original. The problems: lead glass softens at low temperatures (repolishing, ultrasonic cleaning, steam cleaning, even contact with warm acidic solutions such as lime juice can damage the filling). Lead glass rubies require special care and should be disclosed and priced accordingly. The full technical discussion is at gems/treatments/lead-glass-ruby.html (GIA Gems and Gemology; Gübelin Gem Lab; AGL; SSEF; Lotus Gemology).

Source: AGTA treatment disclosure codes (agta.org); CIBJO Coloured Stone Blue Book (cibjo.org); GIA Colored Stone grading standards; AGL treatment nomenclature (aglgemlab.com); Gübelin Gem Lab technical notes (gubelingem.com).

Ruby in India: Manik, the Jyotish tradition, and the Indian market

Ruby holds a special place in Indian culture, trade, and tradition that goes beyond the general global market. India has been a centre of ruby appreciation, trade, and use for at least two thousand years. The Sanskrit tradition called the finest ruby "manikya" (from which the modern Jyotish term "Manik" derives). Ancient Indian texts, including the Arthashastra attributed to Kautilya (circa 3rd century BCE), mention trade in rubies and describe quality criteria that prefigure modern gemological assessment (Ogden, J., Jewellery of the Ancient World, Trefoil, London, 1982, pp. 80–85).

Ruby in the Navratna and Jyotish tradition

In the Vedic astrological tradition (Jyotish), ruby (Manik) is associated with the Sun (Surya), the most powerful celestial body in the Navagraha system. The tradition holds that wearing a natural, unheated ruby of good quality strengthens the influence of the Sun in an individual's birth chart, bringing benefits including vitality, confidence, leadership, and success in authority. The classical texts are explicit that the stone must be natural, free of visible inclusions, untreated, and of good colour to be effective. Behari (1991) describes the requirements as: bright red colour, transparent, without patches or spots, and natural (Behari, B., Gems and Astrology, Sagar Publications, New Delhi, 1991, Chapter on Manik; Brihat Samhita by Varahamihira, Ratna Pariksha chapter).

The Jyotish requirement for an unheated, natural ruby aligns with the commercial top tier of the ruby market: the stones the tradition recommends are the same stones that command the highest prices internationally. This is not a coincidence. The tradition developed in an environment where gem quality was understood empirically across centuries of observation, and the criteria that experienced traders identified as marking the finest stones were incorporated into the astrological framework. The Gemstone Codex presents this tradition with respect, sourced to its primary texts, without endorsing or debunking its astrological claims. The quality standard it describes is real and commercially verifiable.

The Indian ruby market and the gap between tradition and supply

The gap between what the Jyotish tradition requires and what the Indian retail market commonly supplies is significant. A natural, unheated ruby of good colour and clarity in a size suitable for a ring (typically 3 carats or more for Jyotish purposes in some interpretations) is a rare and expensive item. A 3-carat unheated Burmese ruby of fine colour with a Gübelin or AGL certificate commanding a price of approximately USD 20,000–50,000 per carat (indicative, fine quality, auction and dealer market 2023–2025, approximate) is not accessible to most buyers.

The market fills this gap with: heated rubies sold without full treatment disclosure; synthetic rubies (laboratory-created corundum with identical chemical composition) sold as natural; simulants including red glass, garnet, and red tourmaline sold as ruby; and lead glass rubies whose treatment is not disclosed. Each of these represents a different level of consumer protection failure, ranging from incomplete disclosure (heated rubies without clear treatment documentation) to outright fraud (synthetic sold as natural).

The consumer protection guidance for Indian buyers purchasing Manik for Jyotish purposes is simple in principle: any stone for which natural and unheated status matters must have a certificate from GIA, Gübelin, AGL, or SSEF stating the species as ruby (not pink sapphire, not corundum), the treatment status as "no indications of heat treatment" or "no indications of heating," and the origin report if available. No certificate from an unrecognised Indian laboratory, no dealer assurance, and no price point provides equivalent verification. The full buyer's guide for Jyotish rubies is at gems/ruby/buying-ruby-india.html.

Jaipur and the ruby trade

Jaipur processes a significant portion of the world's commercial ruby supply. Rough arrives from Myanmar (via Bangkok), Mozambique (via Gemfields auctions in Singapore and Lusaka), Madagascar, and Tanzania. Jaipur lapidaries cut commercial to fine quality material; the finest unheated Burmese rough typically travels through Bangkok cutting facilities before being certified and sold at international levels. The Johari Bazaar and surrounding lanes contain dealers specialising in ruby at every quality level, from commercial heated goods sold by the kilogram to individual fine unheated Burmese stones with Gübelin certificates. The GIA field report on Jaipur (Gems and Gemology, Winter 2016) documents the scale and structure of this trade (GIA, 2016, "Jaipur, India: The Global Gem and Jewelry Power of the Pink City," Gems and Gemology, Winter 2016).