We deliver your perfect polished stone on time and at the right price.
From in-house sorting to express delivery, we use our global network to negotiate the most competitive prices for you.

From this, we command a reliable reputation, as a trusted partner with a flawless record.

Intergenerational Expertise
We sell more than just premium stones. By choosing Windiam, we help you to buy with our expert knowledge cultivated over three generations of diamond trading. Our expertise helps you thrive in a changing marketplace to ensure your business profits.

Online Inventory
Our stock is updated in real-time, so you’ll always know what we have. While many our stones are HRD and GIA certified; we can source nearly any kind of polished diamond you wish for.

Niche Provider
We are your specialist wholesalers in Baguette diamonds for watch and jewellery manufacturing.

Go Big
Whether you need large white stones or natural fancy coloured diamonds; we have the capability to manufacture them.

Express Delivery
In today’s ultracompetitive market, you need your partner to deliver premium diamonds in the shortest lead time possible. Our global logistics partners (and sometimes even us!) deliver your diamonds when you need them.

Our influential network connects to the best gemologists, artisans and manufacturers of the major world cities. If you need a specific advice or service, we’ll match you with the person or company you need. We nurture our network for your business growth.

Call us to find out more about our polished services here.

Windiam 360
Windiam 360

Windiam 360

Controlled Sourcing
Increased competition makes it tough to meet your customer’s demands. We solve this by training our sourcing specialists to understand, assess and fully meet your requirements. Our meticulous QC department uses Sortoscopes to ensure a minimum rejection of goods. And our global network gives us the edge to supply your customers with what they desire promptly.

Our rough sourcing, polished expertise and optimised production experience meet your customer’s desires in our typically valued manner. When large and expensive stones are required, we’ll allocate rough stones to meet your specific demands.

Memo Program
Windiam understands the more diamonds your customers can inspect before purchasing the more your sales increase. That’s why we’ll loan you the premium diamonds you want on credit, interest-free.

Buy Back
If you have an unsatisfied customer and need to buy back a stone, we’ll offer you financial support as and when required.

‘Cut in Antwerp’ is synonymous with perfection and over 500 years of master craftsmanship. Our Antwerp-based headquarters gives us access to the best polishers in the world. Optimising your customer’s gems regularly provides a lifetime of happiness.

Educate Your Team
Tours of the diamond market improve your understanding of how the top traders operate. Technical training in diamond sorting including the correct use of an eye loupe and Sortoscope. Applying this product knowledge back home will help you stand out in today’s ultra-competitive business.

Special Events
Presenting your collections externally (e.g. trunk shows) is an excellent way to build your brand. We’ll support you by taking your event to the next level with one of our representatives and a premium stones collection.

We can provide you with certified diamonds. Sealed or laser inscribed from the distinguished Hoge Raad voor Diamant (HRD) or Gemological Institute of America (GIA) laboratories.

Call our Antwerp head office to find out how our 360 program can benefit your business.

Staying One Step Ahead
Staying One Step Ahead

Staying One Step Ahead

We work daily with state of the art technology

Meet the M-Screen
A precise, automated melee device that screens round brilliant diamonds from 1.0 millimeter till 20 points for possible lab grown ones, or potential HPHT colour enhancement and simulants.

The technology eliminates the risk of receiving compromised goods.

Optec Industries
This French company have developed an automated optical dimensional control system for round melees diamonds. With its precise cut quality control, it delivers on your specific measurements.

As a preferred partner for many luxury watches and jewellery houses, we save you time and money by:

  • Assorting your goods; every stone you receive from us is precisely as per specification
  • Avoiding return shipments of rejected stones

Both machines have been in operation since 2016 at our Antwerp headquarters. Alongside our in-house sorting team, these investments help optimise your search for the perfect diamonds.

Ask us more or arrange a tour of our technology by calling our Antwerp head office here.

Meet Gon
Meet Gon

Meet Gon

Windiam Director / Owner

“At Windiam, we don’t just buy and sell diamonds. We give all companies the resources and tools they need to thrive.When our clients succeed, we succeed.My favourite part of work is celebrating my client’s success, whether it’s a large sale or the launch of a collection. The relationships we foster are particularly gratifying. I get to know their stories, understand their challenges and learn about their aspirations. These personal relationships drive our business. We are trusted advisors to our clients not just because of our knowledge but because we care about your needs.”

Gon Raz is a 3rd generation diamantaire bringing the heritage and impeccable reputation of his grandfather Dov and father Amos Raz who were among the founders of the Israeli Diamond Exchange.

To speak to Gon, contact our Antwerp head office here