Sapphire: Meaning, Colours, Types and Value

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The sapphire is a blue variety of corundum and one of the most prized coloured gemstones in jewellery. In this guide, you’ll find out about the meaning of the sapphire, its properties and characteristics, its colours, origin, asterism (star sapphire), synthetic varieties, treatments, how it is graded, its use in jewellery and how to care for it. At the end, there is an FAQ section covering the most common questions.

Traditionally, the sapphire is associated with honesty, truth and justice. These meanings stem from the beliefs and history of the courts and the Church, rather than from scientific evidence. Its intense colour and durability, however, are facts, and explain why the stone is so widely used in engagement rings and fine jewellery.

What is a sapphire?

Sapphire is a variety of the mineral corundum, composed of aluminium oxide (Al₂O₃). In its pure form, corundum is colourless; its colour comes from traces of other elements. In gemmological terms, ‘sapphire’ refers to any gem-quality corundum that is not red; red corundum is always a ruby. In the trade, however, ‘sapphire’ without an adjective refers to a blue sapphire, whilst other colours are named after their colour (yellow, pink or green sapphire) and are referred to as fancy.

The name comes from the French saphir, from the Latin sapphirus and the Greek sappheiros. In ancient times, the term did not necessarily refer to corundum and was also associated with lapis lazuli and other blue stones.

For centuries, the sapphire has been worn by kings, queens and members of the Church. Among the famous pieces in the British Crown Jewels are the Stuart Sapphire and the St Edward’s Sapphire. Closer to home, Princess Diana’s engagement ring, now worn by Kate Middleton, is cited by the GIA as the world’s most famous blue sapphire.

Joias com pedra safira — Jewellery featuring sapphires

Video about the sapphire

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Pedra Safira - História e caracteristicas06:30

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The meaning of the sapphire

The meanings attributed to the sapphire stem from tradition and belief, rather than scientific evidence. It is associated with honesty, truth, justice, wisdom and spirituality, and blue is the colour favoured by kings and members of the Church. The yellow sapphire is associated, by those who believe, with creative energy and prosperity.

According to tradition, the sapphire is the birthstone for September and the gemstone for the 5th and 45th birthdays, according to the GIA. The 65th birthday is also known as the ‘sapphire jubilee’.

Properties and gemmological characteristics of sapphire

Mineral and formula: corundum, Al₂O₃;
Crystal system: trigonal (related to the hexagonal system); the crystals are usually barrel-shaped or hexagonal pyramidal;
Hardness: 9 on the Mohs scale, one level below diamond;
Density: approximately 4.00;
Refractive index: 1.762 to 1.770;
Birefringence: 0.008 to 0.010;
Lustre: vitreous to subadamantine;
Splitting and toughness: does not split and has excellent toughness, making it impact-resistant;
Transparency: from transparent to opaque;
Colours: all except red (which is ruby), including blue, pink, yellow, orange, green, violet, grey, black, brown and colourless.

A hardness rating of 9 has a significant impact on the stone’s value and also requires technical skill in cutting. As the Mohs scale does not have equal increments, the diamond – which is just one number higher – is many times harder. Even so, sapphire holds up well to everyday wear and tear.

Sapphire colours and what causes them

The colour comes from traces of elements in the crystal:

Blue: iron and titanium;
Rosa: chromium (when chromium is abundant, the colour is red and the stone becomes a ruby);
Yellow and orange: absorption linked to iron and defects in the crystal;
Green: overlap of blue and yellow absorption bands (vanadium is another pathway);
Violet and purple: chromium combined with iron and titanium, or vanadium.

Some sapphires exhibit colour change, generally appearing blue in daylight or under fluorescent lighting and purple under incandescent light.

Safiras de diferentes cores — Sapphires of different colours

Blue sapphire

Blue sapphires are the best known and most sought-after. The GIA notes that large blue sapphires are easier to find than large rubies.

Among the most famous is the Logan Sapphire, weighing 422.98 carats, from Sri Lanka, on display at the US National Museum of Natural History in Washington. Its blue has a slight violet tinge, and the GIA examined it in 1997 and concluded that the colour is natural and that the stone has not been heat-treated. Other large sapphires include the Star of India (563.35 carats) and the Black Star of Queensland (733 carats). In 2021, Sri Lanka unveiled a 310 kg rough blue sapphire, nicknamed the ‘Queen of Asia’, but the value reported in the press has not been confirmed.

White or colourless sapphire (leucosapphire)

It is corundum without any colour-giving elements. It is used in jewellery as an alternative to the diamond, including in engagement rings, but it has less brilliance than the diamond.

Yellow sapphire

It is becoming increasingly popular as an alternative to diamonds, with a more cheerful feel. Its colour is due to the presence of iron.

Pink sapphire

The colour comes from chromium. The distinction between pink sapphire and ruby is determined by gemmological laboratories.

Violet or purple sapphire

Rare colours, which are sometimes mistaken for amethyst. As amethyst is a much softer form of quartz (hardness 7), the difference becomes apparent in a gemmological test.

Grey, black and brown sapphires

These are also varieties of sapphire. The black ones are usually almost opaque, and some display a star, such as the Black Star of Queensland.

Orange sapphire

It occurs in shades ranging from orange to brownish-orange, due to the presence of iron and defects in the crystal.

Green sapphire

The colour results from the superimposition of blue and yellow absorption bands. It often displays traces of blue or yellow. To compare it with other green gemstones, see tourmaline.

Safira Padparadscha

It is a rare and valuable sapphire, with an orange-pink colour, like a lotus flower. The name comes from the Sinhalese language. Traditionally associated with Sri Lanka, it is now defined by its colour and stability, rather than its origin. For this reason, there is often debate amongst laboratories as to what does and does not constitute a padparadscha.

Origin: where sapphires are found

Sri Lanka: gem-bearing gravel (Ratnapura region) and some occurrences in rock;
Kashmir (India): Paddar sapphires are rare, with an intense blue colour and a velvety appearance, and are considered the benchmark for blue sapphires. Production was high for only a short period, over a century ago, and is now minimal, which is why older stones are highly sought after;
Myanmar: Mogok, in primary and secondary deposits;
Madagascar: Andranondambo and the Ilakaka–Sakaraha region;
Thailand, Vietnam and Australia: Chanthaburi–Pailin, southern Vietnam and eastern Australia, in secondary deposits;
United States: Montana (Rock Creek, the River Missouri, Yogo Gulch);
Kenya: central region (Dusi).

In Brazil, corundum deposits are scattered. Studies cite sites in Minas Gerais, Santa Catarina, Rio de Janeiro and Mato Grosso do Sul, as well as in Mato Grosso and Goiás. Commercial production is limited and cannot be compared with that of other countries.

Asterism: the star sapphire

Asterism is the star-like effect that appears in some gemstones. In sapphire, it is caused by fine rutile needles (the ‘silk’) oriented in three directions, which form a six-pointed star. When two networks of inclusions overlap at an angle of around 30°, the star may have 12 points. The effect is different from chatoyance, which forms a single band of light.

To reveal the star, the stone is cut into a cabochon. The value of a star sapphire depends on its weight, colour and the clarity of the asterism. Synthetic star sapphires also exist, and only a laboratory can confirm whether the stone is natural.

Synthetic sapphire

Synthetic sapphire is grown in a laboratory and has, in essence, the same composition and the same physical and optical properties as natural sapphire. It should not be confused with an imitation, which is a different material (such as glass) that merely resembles a sapphire. It is also used in industry: windows for barcode scanners and spacecraft components are examples.

The first commercial method was flame fusion, the Verneuil process, announced by the Frenchman Auguste Verneuil in 1902 (for ruby) and described in detail in 1904. In this process, aluminium oxide powder is melted in a flame of oxygen and hydrogen; the droplets fall onto a support and crystallise into corundum. The addition of chromium, titanium, iron and other elements produces the colours. This process is still widely used.

Flow (flux): the alumina is dissolved in a molten compound, which acts as a solvent;
Hydrothermal: growth in aqueous solutions, under high temperatures and pressures;
Other methods: Czochralski, Kyropoulos, heat exchanger (HEM), EFG and Bridgman.

To determine whether a sapphire is natural, you need to examine its inclusions under a microscope. Natural sapphires usually contain mineral and liquid inclusions and exhibit linear colour zoning. Trace elements may provide clues, but they are not sufficient proof. For high-value purchases, ask for a report from a gemmological laboratory.

Sapphire treatments

Heat treatment

It is the most common treatment. Controlled heating alters the colour and transparency: it can deepen or lighten the blue and dissolve the rutile inclusions, either partially or completely. Modern furnaces, which reach temperatures in excess of 1,500 °C, have transformed Sri Lankan geuda into transparent blue sapphires since the 1960s. According to the GIA, the majority of rubies and sapphires on the market today are heat-treated. The treatment is traditional and accepted, but a heat-treated stone is not ‘natural’ in the sense of being untreated, and ideally this information should be included in the report.

Dissemination

In diffusion, elements are introduced into the stone at high temperatures. Titanium diffusion (1970s) creates or deepens the blue colour in a thin layer close to the surface. Beryllium diffusion, which gained popularity in the early 2000s, is carried out at temperatures above 1,800 °C and can produce yellow, orange and orange-pink hues, reaching deeper layers. In these stones, surface damage or a new cut may cause the colour to fade. If the stone has been diffused, this information must be included in the report.

Filling and other matters

Cracks can be filled with lead-rich glass; other treatments include flux healing (flux healing), filling cavities and staining. These treatments require greater care and the buyer must always be informed of them.

How sapphires are valued

The evaluation follows the same criteria as for other coloured gemstones, with colour being the most important factor. See also the post on the 4 diamond grades.

Tipos de classificação da safira — Types of sapphire classification

Cor

Whatever the colour, the GIA rates saturation as ranging from strong to vivid. For blues, the standard is the intense, velvety blue of Kashmir. The colour must not be too dark, so as not to lose its lustre.

Purity (transparency)

Blue sapphires usually have some inclusions, but are generally clearer than rubies. Inclusions are a sign of natural origin, but they reduce the value when they compromise durability. Rutile ‘silk’, although an imperfection, sometimes gives the stone a velvety appearance and may appeal to the buyer. Transparency ranges from transparent to opaque, with transparent being the most desirable.

Weight (carats)

Weight is measured in carats. As sapphire is dense (around 4.00, compared with around 3.52 for a diamond), a 1-carat sapphire appears smaller than a diamond of the same weight.

Cutting

The most common cuts are the oval, round, cushion and emerald cuts. Generally, the crown is brilliant-cut and the pavilion is stepped (mixed cut). Star sapphires are always cut as cabochons.

Estilos de corte da safira — Sapphire cut styles

Generally speaking, gem cutters shape the stone according to its colour zoning, clarity and pleochroism (different colours in different directions), and the depth of the cut affects both the colour and the yield.

Sapphire in jewellery

Blue sapphires are widely used in engagement rings, necklaces, earrings and bracelets. Sapphires of other colours, particularly yellow and pink, have gained popularity as an alternative to diamonds. With a hardness of 9 and excellent toughness, the sapphire is one of the most suitable gemstones for everyday wear. It pairs well with diamonds, and to compare it with other coloured gemstones, see the posts on emeralds, aquamarines and gemstone identification.

Caring for sapphires

General cleaning: warm water and mild soap are always a safe bet. A soft-bristled toothbrush helps to clean behind the stone, where dirt tends to build up;
Ultrasound and steam: these are generally safe for untreated, heat-treated or lattice-diffusion-treated sapphires. Avoid using them on stones with filled fractures, filled cavities or dyed stones, which should only be cleaned with a damp cloth;
Chemicals: avoid acids, even mild ones such as lemon juice, on filled or dyed stones. Boric acid powder can damage the surface of even an untreated sapphire;
Usage: Sapphire is resistant to heat, light and most chemicals, but do remove your jewellery when carrying out heavy work.

Sources consulted

Frequently Asked Questions

What is a sapphire?

It is a variety of corundum (aluminium oxide) of gem-quality that is not red. In the trade, ‘sapphire’ without any qualifying adjective refers to the blue variety, and it is the birthstone for September.

What is the significance of the sapphire?

Traditionally, the sapphire is associated with honesty, truth, justice and wisdom. These meanings stem from belief and history, rather than scientific evidence.

What are the properties of sapphire?

Hardness 9 on the Mohs scale, density approximately 4.00, refractive index 1.762 to 1.770, birefringence 0.008 to 0.010, vitreous to sub-adamantine lustre, and no cleavage. The chemical formula is Al₂O₃.

Why is a sapphire blue? Does it come in other colours?

The blue colour comes from iron and titanium. Sapphires occur in almost every colour, such as pink, yellow, orange, green, violet, grey, black and colourless. Red corundum is a ruby.

What is the difference between a sapphire and a ruby?

Both are corundum. The ruby is red corundum, whose colour comes from chromium, whilst the sapphire encompasses all other colours. The distinction between a pink sapphire and a ruby is determined by gemmological laboratories.

What is a Padparadscha sapphire?

It is a rare and valuable sapphire, orange-pink in colour, whose name comes from the Sinhalese language and means ‘lotus flower’. Today, it is defined by its colour and stability, rather than its origin.

What is a star sapphire?

It is a sapphire exhibiting asterism, a six-pointed (or, more rarely, twelve-pointed) star effect caused by rutile needles. It is cut into a cabochon to showcase the star.

Can the sapphire be treated or synthetic?

Yes. Heating is the most common treatment, and there are also diffusion, fracture filling and staining. Synthetic pearls have the same composition as natural ones, and only a laboratory can confirm their origin. Always ask for a certificate when making high-value purchases.

Where do the best sapphires come from, and what determines their value?

Those from Kashmir are the benchmark for deep, velvety blue, but production is minimal. There are also varieties from Sri Lanka, Myanmar, Madagascar and Montana. The value depends on the colour (saturation), purity, weight, cut and natural origin, without any treatment.

How do you clean sapphire jewellery?

Use warm water and mild soap with a soft brush. Ultrasound and steam are usually safe for untreated or heated stones, but filled or dyed stones should only be cleaned with a damp cloth. Avoid acids.

Written by Willy Sievert

Editor of Bahia.ws since its founding in 2009. Based in Salvador, he travels frequently across the Northeast and all of Brazil to keep the guides up to date. Learn more about Willy Sievert →

Published on 23/02/2023 · Updated on 12/10/2026