Popular Mother's Day gifts also among most counterfeited. Here's what to look for when you buy.

For many families, Mother's Day requires the best gift possible, but beware! U.S. Customs and Border Protection agents warn you could easily fall victim to counterfeit goods.

The most popular items counterfeited are also some of the most expensive. They include luxury handbags by Louis Vuitton, many of which are sold for more than a thousand dollars.

Diamonds or trinkets made of gold or silver are also popular gifts for Mother's Day. They can all be bought online or at flea markets, but often at great risk.

"I have seen some very convincing fakes," said Ebis Argueta with National Pawn Shops. She says she doesn’t trust her eyes alone.

In fiscal year 2020, U.S. Customs and Border Protection agents seized more than 26,000 shipments of counterfeit goods. If genuine, they would be worth more than $1.3 billion.

"We feel bad for a customer when they bring it in, because they paid a lot of money for them or it was a gift that they got," said Argueta. She is trained to use a variety of tools to test an item’s authenticity. Counterfeit handbags have tell-tale signs.

"Stitching is number one. The hardware, sometimes it’s a different color," explained Argueta.

Rolex watches are also a common target for counterfeits. "We actually can open the back, look at the movement of the watch and remove the bands and then you can actually see the serial number and the model numbers," said Argueta. She says the way those numbers look and are spaced as well as the weight of the device are clues.

Weight is also a clue for fake AirPods. They are currently a favorite of counterfeiters. Arqueta checks for matching serial numbers. "The serial number goes in here," she said, pointing to the inside lid of the protective case. "And then the serial number should match on the AirPod as well," she added.

Knowing the difference between a natural diamond and one grown in a lab requires special tools. She uses a handheld device designed to confirm a real diamond. However, another device is needed to separate it from manufactured versions.

Inside a chamber and under a glass screen, the diamond will appear blue if it is natural. "If it gives you a pink or green or red, it means it’s not a real diamond. It’s lab grown," explained Arqueta.

The U.S. Customs and Border Patrol warns many counterfeit electronic devices also present potential health hazards. If they are not well made, they can overheat. Agents recommend purchasing goods only from the trademark holder or authorized retailers.