Lifetime free cleaning and polishing service.

Free insured shipping in Europe.

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Find Your Ring Size

Royal Coster
Diamonds Size
MM / INCH (Circumference)
48 / 1.89 48 4½ 8
49 / 1.93 49 9
50 / 1.97 50 K 10
51 / 2.01 51 L 11
52 / 2.05 52 6 12
53 / 2.09 53 13
54 / 2.13 54 14
55 / 2.17 55 O 15
56 / 2.20 56 P 16
57 / 2.24 57 8 17
58 / 2.28 58 18
59 / 2.31 59 R 19
60 / 2.36 60 9 S 20

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why royal coster

We Go Beyond Expectations

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.

Our core values







how do we do this?

Largest stock of loose diamonds in Europe

With 20.000 loose diamonds in stock, we have the biggest collection in Europe. If you’re looking for that one special diamond, we can probably provide you with it!

Our diamond jewelry is handmade inhouse

Our diamond polishers and goldsmiths polish and create the jewelry themselves. In their workshop they create the most fascinating and unique masterpieces.

Four monumental villas in the heart of Amsterdam

Discover something in every building! See how our craftsmen work on diamond jewelry and enter the world of diamonds in one of our luxurious showrooms.

What does this mean?

For every taste

Whatever style you prefer, you are in the right hands with us! From solitaire rings, to tennis bracelets and big statements pieces. We got it all. And if you still can’t find that perfect jewel? Our craftsmen can easily create a one-of-a-kind piece for you.

The most trusted jeweller

Since 1840 many customers have trusted the craftsmen of Royal Coster for their jewelry. Among which royals from all over the world, such as Empress Sisi, King Rama V of Thailand and the Viceroy of China. We work with the highest quality diamonds and our diamond polishers are known for their expertise.

Countless satisfied customers

At Royal Coster we don’t only sell diamonds and diamond jewelry, we create stories of happiness and love. We are proud and grateful to be a part of your love journey.

What do you get?

Lifetime Service

All jewels that have been bought with us deserve the best care possible. Is there a problem with your jewel or did it lose its sparkle? You are always welcome to visit us and together we will make sure you’ll leave as a happy customer with a sparkling bright jewel, as it’s supposed to!

Worldwide Delivery

From Amsterdam to anywhere in the world! We will do anything to make sure that your beloved jewel will end upon your finger, no matter where you are.

14 Day Returns Policy.

Are you unsure about your purchase? All our jewels have a 14 day returns policy. This also includes custom made jewelry or jewelry that was personalized.

royal experience Royal Coster Diamonds, diamond tour, diamond factory

Visit royal coster

Book an experience and learn about our heritage or visit us to see more diamonds & jewelry