Story by F. Scott Fitzgerald, published in Tales of the Jazz Age (1922).
John T. Unger, a teenager from Hades, Miss., becomes a friend of Percy Washington at their Massachusetts preparatory school and goes to spend the summer holiday at the Washington mansion in the wilds of Montana. It is located on isolated land that conceals a diamond mine and a single gem one cubic mile in extent, discovered by Percy's grandfather and concealed from the world. The summer ends when the diamond mountain is located from planes by aviators who land to scale its great peak. With his father and mother Percy disappears into the mine but the mountain disintegrates, burying them and the aviators, while John and Percy's two sisters contemplate the scene of the disaster.