Black flint stones in area of Nakhsh Mountain near Salwa Road in southern Qatar, May 8, 2015
Stones on Appalachian Trail south from Rattlesnake Mountain. Delaware Water Gap, New Jersey, May 12, 2007
A stone from Thorofare Mountain Overlook of Skyline Drive. Skyland, Virginia, May 16, 2007
Volcanic stones along a jeep track along Netafim River in Eilat Mountains, 2 miles north-west from Eilat. The Middle East, March 22, 2001
Stone Mountain Park east from Atlanta, Georgia, view from a plane. December 2, 2003
Large granite stone covered by cracked lichen Acarospora novomexicana (yellow) and firedot lichen Fulgogasparrea appressa (Caloplaca appressa)(?) (red) on Freshman Mountain in Enchanted Rock State Natural Area. Fredericksburg, Texas, December 25, 2018
Passage between stones on Freshman Mountain in Enchanted Rock State Natural Area. Fredericksburg, Texas, December 24, 2007
Weathered stones on a slope of Freshman Mountain in Enchanted Rock State Natural Area. Fredericksburg, Texas, October 27, 2007
Black flint stones on a mountain slope in Harrarah (Al Kharrarah). Southern Qatar, March 27, 2015
Blackened brain-like stones in limestone in Hatira Mountains 4.5 miles east from Sde Boker, near the upper Nahal Hatsats river. The Middle East, April 9, 2001