Together with the pressure from plate movement, this heat recrystallized the limestone into whitish-gray marble and created ripples of brown and yellow rock where impurities were trapped in the ...

Mysterious micro-burrows in desert marble and limestone were probably made by microbes that lived millions of years ago. Exactly what kind of microbes bored into the rock remains unknown, as does ...

CONNOR: Good thinking! I read a bit about limestone on the bus journey. Limestone is a sedimentary rock created by layers of skeletons and shells of sea creatures found in ancient, warm ...