October Birthstones: Opal and Tourmaline


From the rare opal to the mysterious tourmaline, October’s colourful birthstones provide jewellery-lovers with a wealth of possibilities.

If you celebrate your birthday in October, you can lay claim to two extraordinarily beautiful birthstones. Opals are rarer than diamonds, while some varieties of tourmaline are valued at more than £7,000 per carat. Both gemstones come in a dazzling array of colours – and this is the key to their charm.


The origins of opal

The name opal is believed to have originated in two ancient cultures. In India, it was known in Sanskrit as ‘upala’, which means ‘precious stone’, while it was called ‘opalus’ in ancient Rome.

Of course, the true origins of this precious gemstone are far older. After all, it takes between five and six million years for an opal to form. These precious gems are created when silica-rich water seeps into cracks in the Earth’s crust, leaving a deposit when the water evaporates. One of the few gemstones to be formed in this way, precious opals contain up to 10 percent water.

While opals have been discovered across the world, from Ethiopia to Brazil and Madagascar, Australia is the main exporter of this October birthstone. The stone is so important to the country’s identity that, when Queen Elizabeth II made her first visit to Australia in 1954, she was presented with the 203-carat Queen’s Opal, also called the Andamooka Opal.

A spectrum of colour

Unlike the common opal, a precious opal has what is known as a ‘play of colour’. The word ‘opalescence’ was created to describe the captivating way in which the stone refracts and reflects wavelengths of colour, creating a rainbow effect. This amazing natural phenomenon is the result of the unique size and spacing of the silica within the stone and is the key to the opal’s high value.

The opal’s shifting colour has caught the imagination of people throughout history. While the Ancient Greeks believed it protected against disease, the iridescent stone was held up as a symbol of purity and truth in Europe.

Many factors go into deciding an opal’s value, but colour is key. This includes both the body tone, which is the background colour and can range from black to white, and the play of colour that creates the opal’s stunning iridescence.

Wearing opals

In recent years, many celebrities, including Cate Blanchett, Taylor Swift and Jennifer Hudson, have been spotted wearing opal jewellery. However, opals are not just seen as a feminine gemstone. Elvis Presley had several opal rings in his jewellery collection and 1960s icon Andy Warhol collected opals. Perhaps it should be no surprise that an artist who was known for his playful use of colour was attracted to a jewel that changes its hue when it catches the light.

Aside from their rarity, perhaps one reason why opals are not commonly used in engagement rings is that they are softer than many gemstones. On the Mohs scale of hardness, they range from 5 to 6.5 and they can also fracture if they are exposed to a sudden change in temperature. Because they are easily scratched by harder stones, such as diamonds, they should be stored carefully to ensure they do not touch other jewellery in your collection.


The rainbow birthstone

October’s other birthstone is less well known than the opal but is also highly prized for its colour. In fact, this semi-precious stone comes in a wider variety of shades than any other jewel. While the most common tourmaline is black, this gemstone can be any colour of the rainbow.

The hue of each tourmaline will depend on which elements were present when it formed. Iron creates a black, brown or dark blue stone, while lithium-rich tourmalines can be almost any colour. It is not unusual for a tourmaline to be multi-coloured. A popular example is the watermelon tourmaline, which has a green exterior and is pink on the inside. Many tourmalines are dichroic, which means they change colour when viewed from different angles.

Such infinite variety of colour makes this October birthstone a highly versatile choice for jewellery.

A mysterious history

Because they come in such a wide range of colours, tourmalines have been mistaken for other gemstones throughout history.

When, in the 1550s, a Spanish conquistador found green tourmaline in Brazil, he mistook it for emerald. His mistake was only discovered in the 1880s when mineralogists correctly identified the mineral, which is now believed to be the first tourmaline to have been discovered.

For centuries, it was assumed that the red stones in the Russian crown jewels were rubies but they are now known to be tourmalines. The most famous is Caesar’s Ruby, which was correctly identified as a 52-carat red rubellite tourmaline in 1922.

Tourmaline was finally recognised as a gemstone in its own right in the 1870s when American mineralogist Georgie Kunz sold green tourmaline to Tiffany & Co.

The true value of tourmaline

Tourmaline is generally referred to as a semi-precious stone, but this can be misleading. Unsurprisingly for such a diverse gemstone, the value of these stones varies wildly. While some tourmalines are used to create jewellery for those on a budget, others are worth more than rubies.

The price of a tourmaline generally depends on its colour. While the stone’s hue and tone will be taken into account when deciding a stone’s value, the level of saturation is the primary factor. The more intense and vivid the colour, the higher the price tag.

Because tourmalines can easily attract dust, they need careful maintenance and cleaning. Storing your jewellery in a box will help protect it.

Whether you choose an opal or a tourmaline to celebrate your October birthday, you can enjoy owning a stone that is unique and special to you. For peace of mind, consider bespoke jewellery insurance for your precious item. Taking out our jewellery and watch insurance means you can protect your opal or tourmaline jewellery and enjoy it for many years to come.