The culture of mazal grew out of the great European diamond centres of the late 19th and early 20th centuries, particularly in Amsterdam and Antwerp.

These were tightly knit trading communities where diamonds moved quickly between dealers, cutters, brokers and exporters. Written contracts were often impractical.

A handshake was faster.

But speed alone would never have been enough. What made the system durable was the presence of the diamond bourses, which acted as marketplace, regulator and court of arbitration.

Mazal was the language of agreement.

The bourse stood behind it.

For much of its history the diamond trade rested largely in Jewish hands.

This was not accident, and it was not preference. It was the result of exclusion.

Across much of medieval Europe, from around the 12th and 13th centuries, Jews were barred from the Christian craft guilds, shut out of land ownership, and closed off from many established professions. What remained open were the trades others controlled less tightly. Lending. And dealing in small, portable, high-value goods.

Diamonds fitted that life exactly.

A community living under the constant possibility of expulsion, from England in 1290, from Spain in 1492, from Portugal in 1497, learned to hold its wealth in a form it could carry. A diamond was value you could fold into a coat and take with you.

When diamond cutting took root in Amsterdam and Antwerp in the late 16th and 17th centuries, it became one of the few skilled trades genuinely open to Jews, precisely because it was new and lay outside the old guild monopolies. Sephardic (Jews of Spanish descent) families fleeing the Iberian expulsions helped to build it.

The trade became Jewish not by design but by necessity, and it carried its own customs with it.

In those days there were no bourses to arbitrate a dispute.

There was the rabbi.

A broken mazal could be brought before the local rabbi, whose word carried the authority of the community and, in practical terms, the force of law. He did not begin by asking whether there was a contract. He asked whether a man had dealt honestly, and whether he had kept his word.

To be found wanting was to lose something no court could return. Your standing. Your name.

The bourse arbitration panel, when it came, was simply the secular heir to the rabbi’s judgement. The same principle. The same authority. The same reliance on reputation rather than paperwork.

There was also a practical reason why disputes stayed inside the trade.

Courts were not well suited to diamond cases.

Judges rarely understood the technicalities of assortments, qualities, weight tolerances or trade terminology. Even something as simple as whether a parcel matched its description could involve specialised knowledge that only experienced diamantaires possessed.

Bourse arbitration panels, by contrast, were made up of people who handled diamonds every day. They understood how deals were actually made, and they understood the significance of a handshake accompanied by the word mazal.

While the outside world sometimes imagines the diamond trade as informal or chaotic, the reality was quite the opposite. It functioned within a highly structured community system where reputation, arbitration and membership rules created an efficient and remarkably resilient market.

Mazal closed the deal.

The bourse made sure the deal stood. Many bourses historically did not allow companies to become members precisely because companies have limited liability. Membership was personal. A diamantaire stood behind his trades with his own name and reputation. If something went wrong, he could not hide behind a corporate structure.

When arbitration decisions were challenged and taken to court, they were very rarely if ever overturned. Judges generally recognised that the arbitration panels were composed of experienced diamantaires who understood the customs and practices of the trade, and they were reluctant to second-guess their decisions.

Even in modern times the authority of arbitration in the diamond trade remains remarkably strong. In one of the largest disputes in recent industry history, involving claims exceeding one hundred million dollars, the losing party attempted to overturn the arbitration award in the courts of New York. The challenge was rejected and the court upheld the ruling, reaffirming the long-standing principle that arbitration decisions, particularly those made by panels with deep industry expertise, are given significant weight by the court.

Mazal still closes the deal.