Birthstones | A History Written in Minerals

Long before gemstones became associated with particular months, they were valued for their rarity, colour, durability and the extraordinary geological processes that created them.

The modern birthstone calendar is often thought of as an ancient tradition, but the system we recognise today is the result of centuries of evolving customs. While references to twelve gemstones can be traced to the Biblical Breastplate of Aaron and later associations with the zodiac, the idea of wearing a specific stone linked to your birth month only became widespread in the eighteenth and nineteenth centuries. In 1912, the American National Retail Jewellers Association formalised the birthstone list that remains largely unchanged today.

Although many of the stories attached to birthstones are rooted in folklore, the stones themselves also tell us a fascinating story, one of immense geological timescales, extreme pressures, ancient oceans and changing continents.

January — Garnet

Garnet is not a single mineral but a family of closely related minerals that occur in a remarkable range of colours, from deep red to vivid green and even orange. The rich crimson varieties most commonly associated with January owe their colour to iron and manganese within the crystal structure.

Many garnets formed hundreds of millions of years ago during mountain-building events deep within the Earth's crust. Their exceptional durability means they often survive erosion and can be found concentrated in river gravels long after the surrounding rock has disappeared.

Historically, garnets were popular with the Romans and later became a hallmark of Victorian jewellery. Their warm red colour has often been compared to pomegranate seeds, giving rise to the stone's name from the Latin granatus.

February — Amethyst

Amethyst is the purple variety of quartz, coloured by traces of iron within the crystal lattice and altered by natural radiation over millions of years.
For much of history, amethyst was considered as valuable as ruby and sapphire. Vast deposits discovered in Brazil during the nineteenth century dramatically increased supply and transformed it into a more accessible gemstone.

The Ancient Greeks believed amethyst could prevent intoxication, a belief reflected in its name, derived from the Greek amethystos, meaning "not drunk." Today it remains prized for its rich violet tones, which can range from delicate lavender to deep royal purple.

March — Aquamarine

Aquamarine belongs to the beryl family, the same mineral species that produces emerald. Its colour comes from traces of iron incorporated during crystal growth.

Some aquamarine crystals grow to extraordinary sizes, forming within cavities in granite pegmatites where mineral-rich fluids slowly cool and crystallise. These geological conditions can produce transparent crystals measuring several metres in length.

Its name derives from the Latin for "water of the sea", a fitting description for its pale blue-green colour. Sailors once carried aquamarines as protective talismans, believing they could calm rough seas and ensure safe voyages.

April — Diamond

Diamond is composed entirely of carbon, yet its crystal structure makes it the hardest naturally occurring material known.

Most diamonds formed between one and three billion years ago, more than 150 kilometres beneath the Earth's surface under immense heat and pressure. They reach the surface through rare volcanic eruptions known as kimberlite events.

Their exceptional hardness, brilliance and rarity have made diamonds enduring symbols of commitment and longevity. From a scientific perspective, they are equally remarkable — tiny time capsules carrying information about conditions deep within the Earth long before complex life existed.

May — Emerald

Emerald is the green variety of beryl, coloured primarily by chromium and occasionally vanadium. The combination of elements required to form emerald is exceptionally unusual, contributing to its rarity.

Unlike many gemstones that form under relatively stable conditions, emeralds often develop where contrasting geological environments meet, creating complex growth patterns and characteristic internal features known as inclusions.

Emeralds were highly prized in Ancient Egypt, where Cleopatra famously favoured the gemstone. Today, these natural inclusions are often celebrated as part of the stone's individuality and are affectionately referred to as its "jardin" or garden.

June — Pearl, Moonstone and Alexandrite

June is unusual in having three recognised birthstones.

Pearls are unique among gemstones because they are formed by living organisms rather than geological processes. Natural and cultured pearls develop when layers of nacre accumulate around a nucleus within a mollusc, creating the soft lustre that has fascinated people for centuries.

Moonstone belongs to the feldspar family and displays an optical effect known as adularescence — a floating blue-white glow caused by light scattering between microscopic layers within the crystal. This phenomenon creates the shifting, ethereal appearance that gives the gemstone its name.

Alexandrite is among the rarest of all gemstones. A variety of chrysoberyl, it exhibits a dramatic colour change due to traces of chromium, appearing green in daylight and reddish-purple under incandescent light. Discovered in nineteenth-century Russia, it remains one of the most scientifically intriguing gemstones in jewellery.

July — Ruby

Ruby is the red variety of corundum, coloured by chromium. The same mineral species produces sapphire, with colour being the primary distinction between the two.

Rubies often fluoresce under ultraviolet light, a property that contributes to the vivid internal glow seen in some of the finest stones. The most sought-after examples display a colour often described as "pigeon's blood" red.

Historically, rubies were treasured throughout Asia and were believed to contain an inner fire that could never be extinguished.

August — Peridot

Peridot is one of the few gemstones that occurs in only one colour family. Its distinctive green is an inherent property of its crystal chemistry rather than being caused by trace impurities.

Formed deep within the Earth's mantle, peridot reaches the surface through volcanic activity. Some rare examples have even been found within meteorites, making them among the few gemstones known to originate beyond our planet.

Ancient Egyptians mined peridot on the island of Zabargad in the Red Sea, where it became known as the "gem of the sun".

September — Sapphire

Sapphire is another variety of corundum and is renowned for its durability, ranking second only to diamond in hardness.

While blue sapphire is the most familiar, sapphires occur naturally in almost every colour, including pink, yellow, green, orange and the increasingly sought-after parti sapphires that display multiple colours within a single crystal.

For centuries sapphires have been associated with royalty, wisdom and protection. Their combination of beauty and resilience also makes them one of the finest choices for jewellery intended to be worn every day.

October — Opal and Tourmaline

Opal differs from almost every other gemstone. Rather than being a crystalline mineral, it is composed of microscopic spheres of silica arranged in a highly ordered structure. Light interacting with these spheres produces the spectacular flashes of colour known as play-of-colour.

Tourmaline is one of the most chemically complex gemstone families and occurs in an extraordinary range of colours. Some crystals even display multiple colours within a single stone, creating striking natural gradients.

Both gemstones are celebrated for their diversity and individuality, with no two examples ever appearing exactly alike.

November — Topaz and Citrine

Topaz forms within cavities in igneous rocks and can occur naturally in a variety of colours, though many of the vivid blues seen today are produced through treatment of colourless material.

Citrine, the golden-yellow variety of quartz, owes its colour to traces of iron within the crystal structure. Natural citrine is relatively uncommon, and many examples historically sold as citrine were created by heating amethyst.

Their warm colours have long made both stones popular choices during the darker months of the year.

December — Turquoise and Zircon

Turquoise is one of humanity's oldest known gemstones, mined and traded for over 5,000 years. Its distinctive blue-green colour results from the presence of copper and iron, and many cultures valued it as a symbol of protection and status.

Zircon, often confused with cubic zirconia, is a completely natural gemstone with a history stretching back billions of years. Some zircon crystals found in Australia are among the oldest materials ever discovered on Earth, dating to over 4.4 billion years old.

Its exceptional brilliance and rich range of colours make zircon one of the most underrated gemstones in modern jewellery.

More Than Symbolism

Whether chosen because of a birth month, a favourite colour or simply an appreciation for natural materials, gemstones are remarkable records of geological history. Some formed deep within the Earth, others within living organisms, and a few may even have arrived from space.

What unites them is not just mythology, but the extraordinary processes that created them. Each stone carries a story measured not in years, but in millions, and sometimes billions, of years.