World leaders in cutting and distributing optimized light performance diamond cuts

Contact Us Rings Here's Our Story

About Exelco Sightholder Logo

The Exelco Group is a vertically integrated DTC Sightholder. From rough to polished through to finished jewellery our progressive corporate structure allows us full visibility across all distribution channels from manufacturing through to end consumer.

Our groups’ key operations are: rough procurement, manufacturing, and developing complete polished diamond supply programs. Additionally we specialize in long term loose supply and complete jewellery brand & retail concepts supplying some of the world's largest and most prestigious jewellery retailers.

With a history of seven generations in the diamond industry, our unique mix of heritage and innovation, combined with global retail experience, allows us to be one of the only groups in the world able to offer tailor made retail solutions for customers, ranging from unique products through to complete marketing support.

Meet the Owners Diamond Ring

Meet the Owners

Exelco was founded in 1993 by Jean Paul Tolkowsky, Leon Kunstler and Lior Kunstler. Recognizing a demand in the polished market for precision light performance diamonds they grew their business by pioneering the sale of Tolkowsky Ideal Cut Diamonds globally.

Today Exelco is recognized as the market leader in the development of complete diamond supply programs, focusing on proprietary products, from long term diamond supply, through to complete brand, retail & jewellery concepts.

About Exelco

Lior Kunstler is a third generation diamantaire with over 25 years industry expertise.

Lior Kunstler

Jean Paul Tolkowsky is a seventh generation diamantaire with over 30 years expertise.

Jean Paul Tolkowsky

Rough Sources

Exelco are proud to be DTC sightholders; members of a small select group of diamantaires who buy rough diamonds directly from De Beers.

These long term pre-negotiated contracts ensure a consistent supply of rough diamonds catering to the requirements of our international client base.

In addition, our dedicated team of global buyers procure additional rough from multiple sources, including other major global mining tenders and purchases from large rough diamonds traders, with whom we have close working relationships, developed over many years.


Our manufacturing facilities allow us to directly tailor our production to customer’s precise requirements. Our specialism in demand driven manufacturing means leading global brands look to our diamond manufacturing to satisfy the most exacting demands of their business.


Our production ranges from 3gr to 15ct rough, Over 90% of production is Ideal Cut, triple excellent certified diamonds from 0.05 to 5.00ct.. Our locally employed, fully trained master cutters set new industry standards in innovation and excellence using pioneering technologies for enhanced efficiency. H&A Thailand and Botswana are viewed as centers of excellence by leading institutions in the diamond industry. We are BOI-promoted, TLS 8001:2010 and ISO9001:2008 compliant.

Polished Diamond Trading

Our polished diamond department manage the diamond needs of some of the most prestigious luxury retailers in the world.

From product development that caters to individual bespoke requirements right the way through to multiple chain retailers, we meet the requirements of every client.

Close liaison between our polished and rough procurement departments ensure smooth production and efficient supply of.

  • Ideal/Triple-Ex Stones
    Round and Princess 0.15-0.99ct, D-J, IF-SI
  • Optimized Light Performance Diamonds
    Revealing greater fire and brilliance
  • Signature Cuts
    Tailor-made products, created by for specific retailers

We work closely with the leading International Gemological Laboratories with regards to the certification of our diamonds


Exelco provides complete diamond jewellery lines to its top retail partners supplying engagement rings, bridal sets, wedding bands, solitaires, earrings and contemporary fashion jewellery. These collections are designed and created to showcase the diamond allowing the excellence of our diamond cutting and craftsmanship to pervade.

Located in New York our product development department has an intricate understanding of the global market and employs some of the industry's best model makers and jewellery manufactures, ensuring design excellence and market demand.

All jewellery programs have dedicated account managers and marketing teams at their disposal ensuring effective transitions from concept to market.

Our Brands and Signature Cuts


Tolkowsky is the most famous name in diamonds with a history of over seven generations of innovation and excellence. In 1919 Marcel Tolkowsky discovered how to maximize fire, brilliance and scintillation in a diamond creating the Ideal Cut round brilliant. His invention remains to this day the benchmark by which all other diamonds are judged. In 2009 Jean Paul Tolkowsky perfected the Ideal Cut princess diamond and launched the Tolkowsky Ideal cut diamond brand internationally.


Voted the industries number one diamond brand, Exelco supports Tolkowsky’s global retail partners with ongoing initiatives to building consumer awareness and market share through brand differentiation and superior quality.



The Astralis diamond story is one of heritage and innovation from Gabi Tolkowsky the world famous master cutter. His signature diamonds are cut to precise specifications using light performance techniques he learnt whilst crafting the two largest faceted diamonds in the world - The Centenary and the Golden Jubilee. The finished result is diamonds that are brighter than standard cut diamonds of the same shape.


Each Astralis diamond can be traced to its original rough stone via its Kimberley number, ensuring that all diamonds are conflict free and sourced in an ethical and sustainable manner.


Love 100

The 100 facet diamond features an eleven petal flower visible through the table of the diamond. The highest demands of technical excellence and precision symmetry are required to achieve this cut due to its unique facet arrangement, this results in intensified light performance and scintillation.

Love 100


The Mastercut diamond has 89 facets, 32 more than a traditional round brilliant cut diamond. The 8 point star cut into the culet combined with crown break faceting results in a diamond which is visibly brighter than a standard round brilliant.



Exelco is one of the very few diamantaires eligible to supply Forevermark diamonds, a De Beers assurance program for ethical sourcing.

Less than 1% of the worlds diamonds are eligible to be inscribed as Forevermark making them truly rare. Chosen Forevermark partners are those that are not only committed to the highest business, social and environmental standards as set out by the UN mandated Kimberly process but those who meet the exacting standards of cut colour clarity and carat that are also required by De Beers.



Exelco actively measure, manage and integrate responsible business practice and are committed to ensuring the highest standards are always upheld on a social and corporate level.

Corporate Responsibility

Exelco are committed to operating our business with a view to ensuring that our clients are able to rely with confidence on our professional and ethical standards. We carefully monitor the ethical provenance of all our diamonds, only procuring stones from mines that are committed to the highest possible health, safety and environmental standards. We are also deeply committed to the long term sustainable development of the diamond industry and our function as a positive influence within it. To ensure the highest standard of business practices and industry values, Exelco is a member of the Responsible Jewellery Council

As DTC Sightholders we adhere to the Kimberley Process as well as the DeBeers Best Practice Principles more information on which can be found here

Corporate Standards

Exelco is leading example of social accountability within the diamond industry and deeply committed to the health and wellbeing of all employees under our care. Exelco operates an award-winning state of the art manufacturing facility in Thailand. Our cutting facilities are viewed as a centre of excellence by leading institutions in the diamond industry. We are, BOI-promoted and TLS 8001:2010 certified as well as being ISO9001:2008 compliant.

Corporate Standards Corporate Responsibility Responsibility

Latest News

Exelco Sponsor Ms Yutong Wu

17 October 2015

Exelco are pleased to announce their sponsorship of the accomplished designer Ms Yutong Wu and congratulate her on being selected as a finalist of the HRD Awards 2015.

Every two years, HRD Antwerp organises a competition for talented jewellery designers. It is internationally recognised as one of the world’s most important jewellery design competitions today. Its goal is to promote creativity in the design of contemporary diamond jewellery.

Read More

A Cut Above the Rest

17 October 2015

Expert lessons in discovering the best diamonds from master diamantaire Jean Paul Tolkowsky.

The Tolkowsky family changed the shape of the diamond industry with the creation in 1919 of the Ideal Cut diamond. For diamantaire Jean Paul Tolkowsky – an Antwerp Belgium-based master diamond cutter who uses only conflict-free diamonds – that standard has given clarity to his career as the leading authority on these sparkling stones.

Read More

Programs & Retail Partners

Tolkowsky - Sterling

Sterling is the worlds largest jewellery retailer. The Tolkowsky Ideal Cut diamond brand is exclusively available from all Kay Jewellers and Jared stores.

Tolkowsky - Signet

The UK’s largest jewellery retailers The Tolkowsky Ideal Cut Diamond brand is their number one diamond brand exclusively available at Ernest Jones and Leslie Davis.

Mastercut - CMJ

The Company of Master Jewellers is the UK’s largest independent buying group. The Mastercut diamond brand was developed exclusively for their members.

Love100 - Chow Tai Seng

CTS is one of the largest retailer in China with approximately 2,000 points of sales. The 100 facet diamond is exclusively distributed by CTS in China.

Exelco Diamond Belgium - CIMA

Exelco in partnership with CIMA open Exelco Diamond Belgium, a leading bridal brand exclusively selling and promoting Tolkowsky ideal cuts.

Astralis - A.P. Co

Established in 1957 AP Diamond supply the Astralis diamond to more than 100 exclusive retailers across Japan.

Astralis - Nationwide

Over 500 independent jewellery store across Australia and New Zealand make up the largest jewellery group in Australasia.

Tolkowsky - Nationwide

Over 500 independent jewellery store across Australia and New Zealand make up the largest jewellery group in Australasia.

Contact Us

Contact Exelco at one of our worldwide locations

World Map

Exelco NV
Schupstraat 9-11, Suite 75
2018 Antwerpen, Belgium
Tel: +32 3 233 24 52 Fax: +32 3 233 88 41

H&A Cutting Works Ltd
74 Soi Sukhapiban 2 Soi 31
Kwaeng Dokmai, Khet Praves
Bangkok, 10250, Thailand
Tel: +66 2 727 0387 Fax: +66 2 727 0878

H&A Cutting Works Botswana (Pty) Ltd,
PO Box 47679, Plot 64266
Block 3 Industrial
Gaborone, Botswana
Tel: +267 3936222 Fax: +267 3936131

Exelco Asia Ltd
Room 906, 9/F Tower A
Hunghom Commercial Centre, 39 Ma Tau Wai Rd
Kowloon, Hong Kong
Tel: +852 2303 1173 Fax: +852 2303 1560

Exelco Ltd
21 Toval Street,
Yahalom Building,
18th floor Room 88,
PO BOX 115
Ramat Gan 52520, Israel
Tel +972.3.575.2158 Fax +972.3.575.2157

Exelco Diamonds Shanghai Co. Ltd
RM 1401-A88, 14/F, Tower B,
1701 Century Ave.
Shanghai Diamond Exchange Bldg.
Pudong, Shanghai, 200122
Peoples Republic of China/China
Tel: +86 21 5047 8371 Fax: +86 21 5047 8373

21st Dimension UK Ltd
Suite 36, 88-90 Hatton Garden,
Holborn, London, EC1N 8PG, UK
Tel: +44 203 086 7355

Ideal Diamond Trading USA Inc
25 West 45th Street, Suite 705,
New York, NY 10036, USA
Tel: 212-510-8060 Fax: 212-510-8061