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Find Your Ring Size

Royal Coster
Diamonds Size
Internal Diameter / Circumference (mm)​

How To Measure

The Hands-on Method​ Measure an Existing Ring
  • 1. Grab a tape measure, length of string or strip of paper.
  • 2. 2. Wrap one of these objects around your finger. Mark the place where the two end of the measuring object come together.
  • 3. When using string or paper grab a ruler. Lay it on a flat surface and measure to where the marked point is.
  • 4. Use the chart presented above to acquire the correct ring size.
Royal Diamonds at Royal Coster - Royal Coster Diamonds

Royal Diamonds at Royal Coster

From the 7th of july you can get Royal Diamonds in Amsterdam at Royal Coster.

It pleased His Majesty King Willem-Alexander of The Netherlands to bestow the Royal Title upon Coster Diamonds. The formal representative mr. Johan Remkes and the Mayor of Amsterdam mr. van der Laan were present on behalf of the King to declare the title to CEO of Coster Diamonds, mr. Kees Noomen. Coster diamonds was founded in 1840 and in the 175 years of its existence many royalty from all over the world visited Coster to see the most beautiful royal diamonds and the craftsman who make them.

CEO Kees Noomen: "companies can be considered for the Royal title if they are at least 100 years old, are solid and reliable and are leaders in their field, preferably internationally. With pride we can say we fulfill all of these demands and more. We have been one of the most important diamond polishing factories for the last 175 years and will continue to serve our every single tourist who comes to Amsterdam, the city of diamonds. People are used to buying diamonds from us if they want the best and because the royals get their diamonds from us, but now we can say that our customers buy real Royal Diamonds from Amsterdam".

For this occasion we have published a beautiful, richly illustrated book about the history of diamonds, Amsterdam as City of Diamonds and of course the legacy that Manus Coster started 175 years ago. It is available on request and at our museum shop in our villa's in the heart of Amsterdam.

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