Obsidian is perhaps best known in its role as the dark black blade atop ancient spears and axes – but what if we wanted to ...

It was all about the black lava rock that flowed around the edge of nearly every green and fairway, presenting a test that most tour players hadn’t seen before. MORE: The improbably story of the ...

they include both moving lava and the resulting solidified deposits of black rock. Lava flows come in a great variety of shapes and sizes. Nyiragongo is considered one of the most dangerous ...