But how?
He cast his eyes around, and saw the horn full of powder which his friend Jacopo had left him.

He smiled; the infernal invention would serve him for this purpose.

With the aid of his pickaxe, Dantes, after the manner of a labor-saving pioneer, dug a mine between the upper rock and the one that supported it, filled it with powder, then made a match by rolling his handkerchief in saltpetre.

He lighted it and retired.

The explosion soon followed; the upper rock was lifted from its base by the terrific force of the powder; the lower one flew into pieces; thousands of insects escaped from the aperture Dantes had previously formed, and a huge snake, like the guardian demon of the treasure, rolled himself along in darkening coils, and disappeared.
Dantes approached the upper rock, which now, without any support, leaned towards the sea.