Rubies, Sapphires and Emeralds: Origin, Treatment and Value
By the Byrex Gems team, Toronto · Published 25 September 2026
Where the finest rubies, sapphires and emeralds come from, how heating and other treatments affect value, what terms such as pigeon's blood really mean, and why laboratory reports and origin matter.
Ruby, sapphire and emerald have been the most important coloured gemstones for centuries, and they remain central to the fine jewellery trade. Yet two stones that look alike can differ enormously in value because of where they were mined and how they have been treated. This guide sets out the main sources, the treatments you will meet, the colour terms used in the trade, and why independent laboratory reports have become central to buying and selling these gems.
What they are and what colours them
- Ruby is red corundum. GIA explains that chromium causes its colour, which ranges from orangy red to purplish red, and also produces the red fluorescence that can make fine rubies appear to glow.
- Sapphire is corundum in every other colour. In blue sapphire the colouring elements are iron and titanium; according to GIA, only a few hundredths of a per cent are needed, and more iron makes the blue darker. Pinkish orange to orange-pink sapphire is known as padparadscha.
- Emerald is the green to bluish green variety of beryl. GIA attributes its colour to chromium, vanadium and iron.
Ruby origins
Geology largely explains the differences between sources. GIA notes that rubies formed in marble contain little iron, so they tend to show intense red and strong red fluorescence, even in daylight. Rubies from basalt-related deposits contain more iron, which darkens the colour and suppresses fluorescence.
Myanmar (Burma): Mogok
Typical characteristics: Marble-hosted; low iron, strong fluorescence, vivid red
Notes: The historic benchmark source. GIA notes that documented Burmese origin commands a premium for fine rubies.
Myanmar: Mong Hsu
Typical characteristics: Dark violet to near-black cores with red rims
Notes: On the Bangkok market since 1992; heat treatment is used to remove the blue component.
Mozambique: Montepuez
Typical characteristics: Amphibole-related deposit; iron content ranges from nearly as low as Burmese to as high as basalt-type rubies
Notes: Discovered in 2009 and regarded by the trade as the world's largest ruby supplier. Much of the output is heated or, for heavily fractured material, glass-filled; a small share is fine enough to need no heating.
Thailand and Cambodia: Chanthaburi, Trat, Pailin
Typical characteristics: Basalt-related; high iron, weak fluorescence, darker, sometimes purplish
Notes: The leading commercial source between the 1960s and 1990s; production is now sporadic. Routinely heated.
Tanzania: Winza
Typical characteristics: Relatively high iron; some stones show bluish violet colour zones
Notes: Mined since late 2007.
Madagascar
Typical characteristics: Varied
Notes: Andilamena has supplied lower-grade rough since about 2004, much of it for fracture filling; fine rubies and sapphires were found near Didy in 2012.
The rise of Mozambique changed the ruby market. GIA's review of its first decade quoted a dealer who could now assemble colour-matched suites that once took years to collect. It also produced the most expensive ruby sold at auction: the unheated 55.22-carat Estrela de Fura, which made $34.8 million at Sotheby's New York in June 2023.
Sapphire origins
Kashmir (Padar, in the Himalaya)
Typical characteristics: Saturated blue with a soft, velvety appearance caused by very fine inclusions
Notes: Found around 1881, with the finest production in the few years up to about 1887; mining since has been intermittent. GIA says Kashmir origin carries the highest premium.
Myanmar: Mogok
Typical characteristics: Fine blue sapphires
Notes: GIA lists Myanmar among the sources of top-quality sapphire.
Sri Lanka (Ceylon): Ratnapura, Elahera and others
Typical characteristics: Lighter, brighter blues; the classic source of padparadscha
Notes: Sri Lanka's National Gem and Jewellery Authority notes that milky "geuda" corundum, roughly 35 to 40 per cent of the country's corundum, can be heated to transparent blue.
Madagascar: Ilakaka, Bemainty (Ambatondrazaka)
Typical characteristics: Metamorphic; some stones closely resemble Kashmir or Sri Lankan material
Notes: Ilakaka was discovered in late 1998 and is one of the world's largest sapphire deposits. A rush began near Ambatondrazaka in 2016, producing large, highly saturated blues.
Tanzania, Australia and others
Typical characteristics: Varied
Notes: Important commercial sources; East Africa and Madagascar brought fancy-colour sapphires to wide attention in the 1990s.
The Madagascar discoveries illustrate why origin testing matters. In 2017 SSEF issued a trade alert warning that "Kashmir-like" Madagascar sapphires were entering the market, some with fraudulent claims of Kashmir provenance. SSEF showed that inclusions and trace-element chemistry can separate the two, but only with advanced laboratory work.
Emerald origins
GIA's origin research divides emerald deposits into two broad groups. Colombia, Afghanistan and China formed from hydrothermal or metamorphic fluids; Zambia, Brazil, Russia, Ethiopia and Madagascar are schist-hosted, and those stones contain much more iron. Colombian emeralds are also generally lower in the alkali elements lithium, potassium, rubidium and caesium.
Colombia: Muzo, Coscuez, La Pita (western belt)
Typical characteristics: Low iron; saturated, warm green; classic jagged three-phase inclusions
Notes: The western belt accounts for most production and value.
Colombia: Chivor, Gachalá (eastern belt)
Typical characteristics: Tends to be more bluish green, sometimes cleaner
Notes: Lower volumes; bright, clean material is in demand.
Zambia: Kagem and the Kafubu area
Typical characteristics: Higher iron; cooler, bluish green; higher refractive index and specific gravity
Notes: Kagem, 75% owned by Gemfields, is described by GIA as the world's single largest emerald mine. Emeralds form where beryllium-rich pegmatites meet chromium- and vanadium-bearing schist.
Brazil: Minas Gerais, Goiás, Bahia
Typical characteristics: Schist-hosted
Notes: Belmont (from 1978) and Nova Era/Capoeirana (from 1988) in Minas Gerais are the main producers; the best Nova Era material has fine colour and transparency.
Afghanistan: Panjshir Valley
Typical characteristics: Some stones closely resemble Colombian emeralds; higher iron than Colombian on average
Notes: A new, high-quality type appeared in 2017. Research published in Gem-A's Journal of Gemmology in 2021 found a median iron content of about 0.28 wt% Fe₂O₃, against about 0.10 wt% for Colombian stones.
Three-phase inclusions, long treated as proof of Colombian origin, are not exclusive to Colombia. GIA has documented them in emeralds from Afghanistan, China and Zambia and concluded that origin must be assessed from the whole inclusion scene together with spectroscopy and trace-element chemistry.
Heated and unheated
Heating is the most common treatment of ruby and sapphire and is accepted in the trade when disclosed. GIA states that most ruby has been heated and that heating is an accepted treatment for sapphire. It can remove purplish tones from ruby, intensify the blue of sapphire and reduce silk or cloudiness. GIA considers heat treatment durable and permanent in normal wear.
Unheated stones are rarer, and GIA notes that rubies and sapphires with a report from an independent laboratory confirming no evidence of heat command a premium. Detection is not always simple. A 2022 GIA study of Burmese rubies showed that treaters increasingly use temperatures below 1,200°C, which leave rutile silk intact; laboratories therefore study more sensitive inclusions, such as calcite, zircon, mica and spinel, which can alter at 600 to 750°C.
Laboratories express heating in their own terms. GRS, for example, uses "no indication of thermal treatment" for unheated stones, "H" for heating with no residues, graded levels from H(a) to H(d) for increasing amounts of residue in fissures, and H(Be) for heating with beryllium diffusion.
Other treatments to know
- Flux healing. Heating corundum with a flux can heal fractures, leaving residues in the healed fissures. It is closely associated with Mong Hsu ruby, and GIA lists it among the common treatments for Mozambique ruby.
- Lead-glass filling. First flagged by the Japanese laboratory GAAJ in early 2004, this fills extensive fractures in low-grade ruby with high-lead glass. Under magnification the glass shows a flash effect and gas bubbles. GIA warns that even mild chemicals such as lemon juice can damage it and that such stones should be cleaned only with a damp cloth. GRS describes heavily filled stones as "composite ruby". Glass-filled and diffused rubies are worth significantly less than heated rubies.
- Beryllium diffusion. In the early 2000s, laboratories found that corundum was being heated above 1,800°C with beryllium, producing orange to padparadscha-like colours at first and later altering the full range of sapphire and ruby colours. GIA notes that the treatment can penetrate the whole stone, and some cases require mass-spectrometry chemical analysis to detect.
- Emerald oils and resins. Most emeralds have surface-reaching fractures, and GIA reports estimates that 90 per cent or more are fracture-filled. Fillers range from oils, with cedarwood oil standard in Colombia, to waxes and artificial resins. GIA describes clarity enhancement as minor, moderate or significant; GRS uses a scale from none and insignificant through minor and moderate to prominent. Ultrasonic and steam cleaning, heat and solvents can disturb fillers, so warm soapy water is the safest cleaning method.
Disclosure is not optional. GIA points out that the US Federal Trade Commission and trade bodies including AGTA and CIBJO require treatments to be disclosed.
Colour terms: pigeon's blood, royal blue, padparadscha
Trade names such as "pigeon's blood" for ruby and "royal blue" for sapphire appear on some laboratory reports, but they are not universal grades. At the 2016 CIBJO Congress, speakers noted that each laboratory applies its own criteria and that reports can conflict, especially for blue sapphire. SSEF, for instance, restricts "pigeon blood red" to rubies with vivid, saturated red, even colour, strong fluorescence and no indications of treatment, and applies it by appearance rather than by origin, so marble-type rubies from several countries can qualify. For padparadscha, GIA describes the trade range as light to medium pinkish orange to orange-pink. When comparing reports, read the laboratory's own definitions.
What drives value
- Colour. GIA calls colour the most significant factor in ruby's value, with pure, vibrant red to slightly purplish red at the top. For sapphire, velvety blue to violetish blue in medium to medium-dark tones is most prized; for emerald, bluish green to pure green with vivid saturation and a tone that is not too dark.
- Clarity. Rubies are rarely free of inclusions, and visible ones reduce value; fine rutile silk can improve appearance by scattering light. Emeralds are expected to contain inclusions, the "jardin", so eye-clean stones are especially valuable.
- Size. GIA notes that fine-quality rubies over one carat are very rare, and price per carat rises sharply with size for fine material.
- Treatment. Unheated and untreated stones, confirmed by a report, command a premium; GIA notes that diffused and glass-filled rubies are worth significantly less than heated ones.
- Origin. For fine stones, GIA notes that documented Burmese origin adds a premium for ruby, that Kashmir origin carries the highest premium for sapphire, and that an independent origin determination adds to an exceptional emerald's provenance, as does the history of the Colombian emerald region. GIA stresses that every source produces a wide range of quality, so origin never replaces quality.
The auction record books show all of these factors working together. The Regent Kashmir, a 35.09-carat unheated Kashmir sapphire, set a per-carat record for sapphire of about $272,000 at Christie's Hong Kong in May 2025, and the Aga Khan Emerald, a Colombian stone of about 37 carats, became the most expensive emerald sold at auction at Christie's Geneva in November 2024. Our companion article on record auction sales covers these results in detail.
Why reports and origin matter
Treatment status and origin cannot be judged reliably with a loupe. Laboratories combine microscopy with spectroscopy and trace-element analysis such as LA-ICP-MS, and even then origin is stated as an expert opinion. That is why significant stones are usually traded with reports from leading laboratories. Byrex stones carry reports from laboratories such as GIA, GRS, SSEF and others, and the report should always be read alongside the stone itself.
For enquiries about rubies, sapphires and emeralds with laboratory reports, please email info@byrex.com or send a WhatsApp message to +1 (437) 450-3786.