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With your purchase of a Sarah Ho piece of jewellery, you will receive a Sarah Ho Certificate of Authenticity that will provide full details of the metals and the diamonds and gemstones set in the item.  This certificate will include the purchase of date and a signature from Sarah Ho or member of the team. This will allow you to bring your jewellery to us for a free clean and polish within the first year of purchase.

The standard within the jewellery trade is that any diamond over 1.00ct will be accompanied by a certificate.  This will be provided by us, from an established gemstone authority.  Other precious gemstones, such as sapphires, may also have a certificate if they are substantial enough.  

Sarah Ho works with natural pearls and many of these will also be accompanied by a certificate.  Large pearls will have a certificate, some small pearls may have a pearl quality report as they are too small for their own certificate.

Below is a list of gemstone authorities where you can find out more about each.


The Assay Office

In the UK, all items made from silver, gold and platinum must be assayed.  This is a where the metal is tested and stamped according to what type of metal it is ie. gold and it’s fineness, ie 18ct.  This hallmark, so called because the assay office originated at Goldsmiths’ Hall where the assay is done, is one of the oldest forms of consumer protection.  It is a legal standard that shows the customer exactly what they are buying.  All Sarah Ho jewellery is marked with the Traditional fineness mark, the millesimal fineness mark, Sarah Ho’s makers mark, the London Assay office mark and the date letter mark.


These marks guarantees provenance by telling us where the piece was hallmarked, what the article is made from, and who sent the article for hallmarking.




Established in 1931, Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, coloured stones, and pearls.  A public benefit, non-profit institute, GIA is the leading source of knowledge, standards, and education in gems and jewellery.


The diamond grading reports produced by the GIA are the international jewellery industry’s benchmark for grading standards.




DANAT is the world authority on natural pearls - this institution is based in Bahrain and uses advanced technology to test and certify natural pearls. 


DANAT was established as the guardian of global gemmological excellence. It plays a vital role in ensuring, protecting and enhancing public trust in pearls, gemstones and jewellery.  DANAT is an authority on industry standards, scientific knowledge and education, and is committed to maintaining the highest standards of professional and personal ethics.


With Bahrain’s illustrious pearling history and world standing as a premier location for natural pearls, it was only logical to establish the Pearl & Gem Testing Laboratory in 1990.  DANAT goes beyond its role as a certifying authority. It is dedicated to developing the local and regional pearl and gemstone industry.  And to foster this tradition, it offers training programmes to a new generation of gemmologists both in Bahrain and in the region.





Gemmological Certification Services (GCS) is an independent gemmological certificate provider for diamonds, gemstones and pearls.  GCS is a leader in the analysis of mounted coloured gemstones.



Gem & Pearl Lab

The Gem & Pearl Lab provides nationally recognized reports for coloured gemstones and pearls. The reports contain authoritative advice on the application of gem and pearl descriptions within jewellery




The Swiss Gemmological Institute is part of the Swiss Foundation for the Research of Gemstones (SSEF: Schweizerische Stiftung für Edelstein-Forschung) and works independently on a scientific basis. The function of the SSEF laboratory is to analyse precious stones and issue test reports for diamonds, coloured stones and pearls.  All laboratory gemmologists have a scientific and gemmological education and work on a high level of experience and integrity. The laboratory is equipped with the most modern analytical instruments. This ensures that the authenticity of gemstones, origins, and possible treatments can be tested in the most scientific and reproducible manner.








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