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Our legacy of 175 years of diamond craftsmanship

Inside Coster

About us

The world’s oldest and most trusted diamond factory has a rich and compelling history. Royal Coster Diamonds is around for a long time, dating back all the way to at least 1840. Actually, Mr. Coster founded his company before that date, but we just cannot prove it. Therefore, we stick to what we do know. Let us tell you more about our eventful history. A few of our highlights are:

How we cut the Koh-I-Noor for the Queen of England

In 1852, our Master Polishers Fedder and Voorzanger went to London to repolish the Koh-I-Noor for Queen Victoria. This diamond is still the center stone in the Crown Jewels.

In 1852, our Master Polishers Fedder and Voorzanger went to London to repolish the Koh-I-Noor for Queen Victoria. This diamond is still the center stone in the Crown Jewels.

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How we Polished the Famous Star of the South Diamond

Presumably the first diamond from Brazil to receive international fame. We turned the rough diamond into the elegant oval form with its unique color scheme it is today.

Presumably the first diamond from Brazil to receive international fame. We turned the rough diamond into the elegant oval form with its unique color scheme it is today.

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How we Created Queen Juliana’s Diamond Watch

Our connection with the Dutch Royal House is one we treasure deeply. So when our late Queen Juliana celebrated her 50th birthday, we wanted to give her something special.

Our connection with the Dutch Royal House is one we treasure deeply. So when our late Queen Juliana celebrated her 50th birthday, we wanted to give her something special.

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A million tales to tell

Famous Visitors & Other Milestones

The Story of King Willem III

In 1862, King Willem III visited our diamond polishing factory. However, he was not ‘just another royal visitor. He and Martin Coster, were actually quite close. Dare we say: even friends?

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The Story of Sisi

In the spring of 1884, the Empress Elisabeth of Austria-Hungary - who her father affectionately called “Sisi” - visited Amsterdam and Royal Coster Diamonds.

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The Story of King Rama V

In September 1897, King Chulalongkorn the Great, also known as King Rama V of Siam (Thailand) paid a visit to Amsterdam and Royal Coster Diamonds.

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More Facets, more sparkle, more fire: the Royal 201

In 2007, we created the Royal 201. Praised for its great brilliance, the Royal 201 is an example of further development and perfecting of existing shapes.

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Timeline

Royal Coster Diamonds has been around for a long time, dating back all the way to 1840. That year diamond cutter Moses Elias Coster founded Royal Coster Diamonds in a factory near the Waterloo Square, located in the heart of Amsterdam. The timeline tells everything that happened since then:

Explore our Heritage

Everything about that sparkling little stone

Diamond Education

Brief History of Diamonds

Have you ever thought about the origin of a diamond? To learn more about its history we have to go back as far as the 4th century BC and dive deep into the earth.

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Amsterdam City of Diamonds

For 400 years, Amsterdam is called the City of Diamonds. But the story of how Amsterdam became the diamond capital of the world, actually started over 600 years ago in Southern Europe.

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Starting the Diamond Museum

In 2007 we opened our own Diamond Museum to share our passion for diamonds with the public. Let us take you on a journey of the diamond life cycle.

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Our Royal Legacy

The day King Willem III set foot in our establishment in 1862, we could proudly call ourselves purveyor of jewelry to the Dutch royal household

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Carat

The weight of a diamond is measured in carats. One carat equals 200 mg and 100 points. A diamond of 25 points is a quarter of a carat or 0.25 carats

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Color

The color of a diamond – or rather the lack of it – relates directly to a diamond’s value and quality. A diamond that consists of carbon only is pure white.

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Clarity

Clarity refers to the amount and size of inclusions inside a diamond. These are imperfections like fractures, tiny parts of carbon or cavities.

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Cut

The cut is the diamond’s shape and the quality of that shape. This is the only C that the diamond worker can influence and show his skills.

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Good to know

Before you buy

Why buy a Diamond?

People around the world dream of owning at least one piece of diamond jewelry. But what is the attraction of that sparkling beauty?

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What is a Diamond Certificate?

The certificate is a report that proves that all of the 4 C’s are in place. It is a written document that guarantees the quality of the diamond.

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Our 8 Diamond Guarantees

#3 Personal and honest advice: our diamond consultants speak over 35 languages to help you find your perfect stone.

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Our VIP Service

Our list of customers is rich and long. We are proud to be the supplier of diamond jewelry for celebrities, royalty, and captains of industry.

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