Dealers are seeing an unprecedented amount of interest in gold, much of it from first-time buyers, to take advantage of its role as a safe haven in times of stress or unexpected "black swan" events like Brexit.

"The speed at which people are purchasing gold is unprecedented," said Joshua Saul, CEO of The Pure Gold Company, where Hall bought and keeps her Britannia coins.

"We are seeing people convert as much as 40 to 50 percent of their net worth into physical gold, (compared to) 5 to 10 percent in the past," he said.