It was a golden year for international trade through the Miami Customs District in 2012, as South Florida’s airports and seaports handled a record $124.73 billion worth of trade and cracked into the nation’s Top 10 customs districts for the first time.

But the Miami district’s top exports and imports were also golden. Since 2009, gold from countries such as Colombia, Mexico, Guyana and Peru has been South Florida’s top import as skittish investors bought the precious metal, pushing its price to lofty heights. In 2012, gold also became the top export of the Miami district, which includes airports and seaports from Miami to Key West.

Last year the district imported a record $7.25 billion worth of gold — a 42 percent increase over the previous year, according to new U.S. Census Bureau data analyzed by WorldCity, a Coral Gables media company that focuses on U.S. connections to the global economy.

But almost as quickly as the gold arrives, it is shipped out, primarily to Switzerland and to other European countries in smaller amounts. Last year the Miami district exported a record $7.93 billion worth of gold.

The gold business is a “relatively recent phenomenon,” Ken Roberts, president of WorldCity, said at a Trade Connections event in Coral Gables Friday that analyzed the past year’s trade numbers.

Global economic uncertainty, he said, has driven people to the safety of gold and that has pushed up prices. Not only are central banks buying gold, so are many jittery investors.

Miami became the nation’s leading importer of gold in 2009 but imports only totaled $2.14 billion then. Over the past 10 years, the Miami district’s gold imports have increased by 2,420 percent and gold exports are up a whopping 13,433 percent. That corresponds with a huge run-up in the price of gold over the past decade — from around $300 an ounce in mid-February 2002 to $1,730 an ounce in mid-February 2012.

Roberts noted that overall, Miami district exports increased to a record $73.3 billion, up nearly 6 percent from the previous year, and imports totaled a record $51.4 billion — a 17 percent increase.

Most interesting, Roberts said, is that the Miami district made its move into the ranks of the nation’s Top 10 customs districts, by value of trade, at a time when the U.S. economy has been sluggish. But 30 percent of Miami’s trade is with South American, Central America and the Caribbean, and many of the Latin economies have been relatively resilient throughout the U.S. downturn.

Brazil remained the Miami district’s No.?1 trading partner in 2012 with $16.4 billion in total trade — a 6.4 percent increase.

“Brazil has had a tremendous decade and they’re a little smug about it,” said Scott Miller, a senior advisor at the Washington-based Center for Strategic and International Studies and former director of global trade policy at Procter & Gamble. “It’s a tough place to do business and they know it and don’t seem to want to do much about it.”

Miami traders acknowledge that restrictions and high tariffs make the Brazilian market difficult, but Latin America’s largest economy is so big and diverse that it’s still very attractive. Brazil also is the top source of international visitors to Miami-Dade County.

Colombia, with $9.89 billion in trade with the Miami district, was the 2012 runner-up, and Switzerland, with $8.8 billion in trade with South Florida, was third.

But trade statistics only tell part of the story of international commerce.

Miller pointed out that increasingly, world trade involves the exchange of components rather than finished goods. If one takes out oil, he said, half the world’s trade is in components.

He pointed to Apple’s iPhone, which is made in China from U.S. and Japanese chips, a screen from Malaysia and other components from around the world. “So many things today are made in the world,’’ rather than manufactured start to finish in one location, said Miller. “What is really being done is that we make things together.’’

Every iPhone that is imported into the United States, he said, adds $178 to the U.S. trade deficit, but that doesn’t take into account all the jobs created by Apple’s inventions and design development, its sophisticated customer service system and its marketing apparatus.

“Stop looking at trade as a competition,” he said. “It’s a mutually beneficial exchange.”