It’s a young adult mystery set in Four Corners area (Colorado, New Mexico, Utah and Arizona). A family moves to the Four Corner Area and the teen aged kids get involved with a museum. The mystery involves oil and artifacts from the area. The name of the book include the words “Black Gold,” but I’m not sure. I read the paperback in the later 50s or early 60s.
“Black Treasure” by Roger Barlow.
“Sandy Steele and Quiz Taylor constructed an oil reservoir
analyzer as their entry in the Science Fair. They didn’t win first
prize, but they were offered summer jobs in the oil fields of Four
Corners. This book is the story of that action-packed summer. As the
boys search for oil and uranium, they must unmask a dangerous
masquerader!” – See more at: http://www.whatsthatbook.com/?xq=20255#sthash.BkhQjjwI.dpuf
“Black Treasure” by Roger Barlow.