DIA Grading Laboratory is a South African owned company specialising in Diamond and Tanzanite Grading as well as Jewellery Evaluations.

We are a local laboratory that grades to international standards, keeping up to date with industry changes and using top of the line equipment such as the GIA DIAMONDCHECK™.

DIA Certification - Buy with Confidence!

We as industry experts provide you with a comprehensive report for all Diamond and Tanzanite Stones or Jewellery, providing you with the peace-of-mind that you are getting what you paid for.

We offer Diamond Grading, Tanzanite Grading, Jewellery Appraisals as well as other services.

About DIA

DIA certificates and reports are trusted by diamond manufacturers, jewellery retailers and consumers alike. Our ambitious standards and knowledge are just some of the reasons why we are one of South Africa’s most trusted and respected laboratories in the industry. Our pricing is competitive, and we always offer a personal approach to each and every client.

The company was established in 1996 and has grown and serviced the industry with accuracy and consistency for more than two decades.

The company was established in 1996 by GIA qualified grader Lesley Tsakos, and has continued to grow and service the industry for the past 26 years.  Now owned by daughter Nichola van Niekerk and long standing colleague Nicolette van Niekerk, the company is continuing to grow on the strong foundation on which it was built.  In 2017 the company expanded its services to include Tanzanite grading as well as Jewellery Valuations.

Grading Services

To buy and sell such a precious commodity, you need precise standards of comparison which is where the Four C's come in. The DIA Diamond Certificate will provide you with this important information.

Diamond Guide

We offer a short guide on how to identify a diamond's characteristics and possible quality through the following: Common Shapes, Carat / Weight, Colour, Clarity, as well as a Diamond Analysis

Tanzanite Guide

​Tanzanite is a blue to violet gemstone which is a member of the zoisite mineral group. Tanzanite is pleotropic, which means that it reflects different colours depending on the viewing angle.

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