But not all experts agree.
Tiffany Briggs, an assistant professor at Florida Atlantic University specializing in coastal morphology and geology, said the sand in Delaware and Maryland does differ.
The sand in most of the northern regions of the East Coast — including Delaware — came from glaciers melting 18,000 years ago, she said.
The Delaware beaches were about as south as that went, she added.
"When that ice sheet started melting, it released a lot of gravel and sand found along the Delaware coast," she said. "As you move farther south, the coastline is based much more on rivers. Maryland starts to pick up more of the river influence."
What that means, she said, is that the beaches made up of ancient river sediment have finer sand than beaches made up of sand from melting glaciers, which tends to be more pebbly.
But to most beachgoers, there isn't much of a difference in the sand up and down the coast.