The video starts by showing panels of what looks like Carrara marble and then describes how the masons noticed the fossils. We get a mason exclaiming how they had no idea what they had found, but fortunately they told someone who did, who then contacted Philip Gingerich, who in addition to studying Darwinius masillae, studies whales. Gingerich and team went to Egypt and confirmed that the whale fossils in the limestone slab were unusual. They also found fossils from mammals that lived 20 million years later, about 18-20 million years ago, but were not part of the stone being quarried.
The story illustrates several of my favorite aspects of building stones. One is how the quarries open up new areas for geologists to explore. Two, building stone has many stories to tell. And three, stone gets shipped around the world so it isn't odd to find Egyptian rock in an Italian quarry, which may then ship that stone to the United States. It's just too bad that the stone didn't really end up in a countertop.