The Belgium pavilion's colonial section drew undue attention from fairgoers. Present German, Italian and Japanese foreign policy tilted toward colonial expansion, searching for new markets and especially raw materials. Count Robert van der Straten Ponthos, Belgian Ambassador to the United States professed: “We maintain the open-door policy and all nations may buy and sell in the Belgian Congo on an equal footing with the mother country.”
To counteract any adverse thinking among Americans concerning Belgium's colonial policy, two motion pictures depicted the social and industrial progress in the modern day Congo. And Jules D'ans, manager of the colonial section, insisted his nation would never allow Hitler to take over the Belgium Congo, no matter how much the dictator desired it.
But international concerns aside, most fairgoers flocked to the colonial exhibit for one reason, its display of the famed Belgium diamonds. While insurance companies insisted the actual value of the collection must be kept secret, well established professionals estimated the total value at $20,000,000.
The diamonds arrived in thirty-one packages but remained at the United States Custom House while the exhibit area was completed. A few weeks later, the cartons were placed in three large steel containers and delivered by armored car to the Flushing Gate of the fairgrounds. Six detectives and four uniformed patrolmen stood guard while the boxes were carried into the display area.
Twenty-nine Belgium firms contributed diamonds for the display. Housed in twenty-six velvet lined cases, the diamonds came in all sizes, running from eighty-five carats to one of twenty-thousandth of a carat. The colors ranged from crystal-clear to the more uncommon yellow, green and blue-white. This smallest stone was placed in a microscope so visitors might enjoy its eighteen facet surface.
To complete the display, a series of rock crystal models displayed the process through which a diamond must pass before it is place in its final setting.
Interestingly, although the food aficionados praised Belgium's eatery, Turkey's restaurant hosted the luncheon following the diamond exhibit's opening.
On June 16, the diamonds briefly left their secure home. In celebration of Belgium Colonial Day, fourteen young women from Bonwit Teller donned evening clothes and the diamond jewelry for a fashion parade on the “royal train” first used by King George and Queen Elizabeth of Great Britain. Twenty-four Belgium gendarmes and ten fair guards, along with two armored cars staffed with city detectives, escorted the diamond-clad models from the United States Building to the Belgium colonial exhibit.
In mid-September, Belgium authorities added the world's only golden diamond, the sixty-six carat Golden Maharajah, to complete its display.