Obsidian is perhaps best known in its role as the dark black blade atop ancient spears ... rainbow obsidian is both rock and glass. However, this isn’t the same kind of glass that’s used ...

Expansive lava flows in the Sáttítla Highlands was captured by satellites ahead of the recent designation of the area as a national monument.

Black lava rock blankets the landscape, and its purpose isn’t just visual. Several shots on the Nicklaus-designed track take you directly over these lava rocks, and every hole features views of ...