Nobody can say why the Virgin of Guadalupe would appear on a hunk of rock formed millions of years before the birth of Jesus.
But David Nunez says the image is unmistakable — a bluish-black stain on the football-sized rock outlines what looks like the Holy Mother.
Nunez's father found the partially buried boulder while looking for landscaping rocks in an Oakdale orchard. Nunez and his father, Jesus — both Catholics from Merced — insist that it's hard to dispute that the image resembles the famous image of the Virgin of Guadalupe.
Friends have called it a miracle.
Father Harvey Fonseca, of Livingston's St. Jude Thaddeus Catholic Church, isn't so sure.
He recalled a time when a window featured streaks that also seemed to mimic the Virgin Mary.
"People see what they want to see," said Fonseca, who hasn't examined the rock. "It's usually just a coincidence when something looks like something else. For me, it would have to be a great likeness. Then again, God is the one who makes mineral formations, so if he chooses to have an image appear on a rock, he can do it."
The rock is a 14-pound caramel-brown and chalkboard black hunk of gneiss, a banded metamorphic rock that started out as sandstone and shale, according to Rob Rogers, a geology professor at California State University, Stanislaus.
Rogers didn't examine the rock in person, but reviewed several photos e-mailed to him.
The original sandstone and shale were deeply buried and subjected to high levels of heat and pressure, probably when today's Sierra Nevada were formed 40 million to 140 million years ago, Rogers said.
The rock's rounded edges suggest that it was moved by water from the mountains into the valley, probably during a flood event in the past 3 million years, he added.
The Virgin of Guadalupe is said to be an image of Mary, the mother of Jesus Christ. According to Catholics, Mary appeared to a Mexican peasant named Juan Diego in the 16th century.
To prove it was a miracle, her image then formed itself on Diego's cloak. People say appearances of the image since then indicate some kind of religious sign.
Historically, appearances of the Virgin of Guadalupe are associated with hope and healing, said Max Hallman, a professor of humanities at Merced College.
"With all the economic problems and stress in our area, some may interpret it as a hopeful sign," he said.
Like Fonseca, however, Hallman points out that people will see what they're inclined to see.
"Culturally, people in India may have seen a Hindu goddess on it. If you've never heard of the Virgin of Guadalupe, you wouldn't have seen it. Visions are culturally dependent," he said.
Rogers, the geologist, said he couldn't see the image in the e-mailed photos of the rock.
"I must lack imagination," he said.