How do pearls get their colours?

Sep 12, 2023

South Sea pearls at The Perth Mint

From classic white to vibrant shades of pink, purple, and gold, pearls come in a stunning array of colours. Some pearls even boast mesmerising overtones, showcasing dazzling multicolours.

But have you ever wondered what determines the colour of a pearl? Well, it’s actually the mollusc’s lip, the outer part of its shell, that helps to influence the final colour of the pearl.

Take the illustrious black Tahitian pearls, for example. These rare gems come from the black-lip pearl oyster (pinctada margaritifera). Its shell boasts hints of grey and silver, creating the perfect canvas for these naturally formed black pearls. This is the only mollusc that can form natural black pearls.

Alternatively, the silver lipped oyster (pinctada maxima) is famous for producing large silver and gold South Sea pearls.

Another way pearls get their colour is from microscopic pigments inside the conchiolin layer. Conchiolin, the organic ‘glue’ that holds the aragonite layers together, acts like cement in a brick wall structure.

When the conchiolin is pigmented with different colours, these pigments shine through the thin crystalline layers, creating a stunning display of blue, grey, yellow, green, bronze, black, pink, and orange hues on the pearl's surface.

Lastly, the prismatic layers of the pearl, made up of semi-transparent aragonite platelets, play a role too. When light strikes and penetrates the pearl's surface and layers, it refracts back in a full spectrum of colours. This amazing phenomenon is what adds an iridescent overtone to the pearl.

Cultured pearl types and colours

There are four main types of cultured pearls: Akoya, freshwater, South Sea and Tahitian.

Akoya cultured pearls

The classic pearl used for jewellery, especially single-strand necklaces, is the Akoya cultured pearl. These beautiful pearls are well-known in the U.S and other western markets for their white or cream-coloured hues. Both Japan and China are major producers of Akoya pearls.

Though the smallest of all cultured pearls, Akoya pearls are known to be inherently round with a bright pearly lustre and neutral colours.

Freshwater cultured pearls

With an unparalleled variety of sizes, shapes, and colours, freshwater pearls offer endless possibilities for creating stunning jewellery pieces. Their affordability makes them a go-to choice for those looking for pearls at a lower price point. Often cultivated in the serene waters of freshwater lakes and ponds, multiple pearls are often grown within a single oyster, resulting in an abundance of these beautiful gems. Sourced predominantly from China, freshwater cultured pearls come in subtle pastel shades of white, cream, yellow, orange, pink, blue or purple.

South Sea cultured pearls

These rare treasures hail from northern Western Australia, Indonesia, and the Philippines. Shimmering in hues of white, silver, and gold, their impressive size, thanks to a lengthy growth period of two years, and their thick nacre (mother-of-pearl), are the result of the pristine waters in which they grow.

Tahitian cultured pearls

Cultivated with care in the stunning islands of French Polynesia, with Tahiti being the shining star among them, these black pearls showcase an exciting array of colours. From striking greys and blacks to warm browns, these pearls may also have iridescent overtones of blue, green, purple, or pink.

Colouring pearls

Dyeing the pearl is another way to change its colour. For example, the majority of black pearls on the market that are not Tahitian pearls, have been coloured.

The Perth Mint jewellery boutique

You can find The Perth Mint’s jewellery store inside our landmark heritage listed building, established by Britain’s Royal Mint in 1899 at our iconic East Perth site in Hay Street.

Our elegant jewellery boutique is home to some of the world’s most beautiful pearl jewellery. Many of our high-end, hand-selected jewellery pieces are accompanied by a certificate of authenticity, as well as the peace of mind that comes with choosing to make a purchase from a Government of Western Australia-owned enterprise with a long-standing reputation for quality and integrity.

Our experts will happily assist you to try on stunning pearl jewellery so you can see how it looks against your skin, ensuring your masterpiece reflects your true individuality.

Come and explore today or book an appointment now.