You don't have any saved articles. Our scientists have been looking for a rock that formed so long ago it was on Earth before complex life lived on land. Called Lewisian gneiss, it’s the oldest rock ...

know the difference between contact and regional metamorphism we will use these rock names: schist, gneiss, greenstone recognize that different minerals occur at different conditions of temperature ...

By Becky Nelson I have been a rockhound since I was old enough to pick up a pretty rock. My kitchen sink-shelf has several “beauties” that I have picked up on walks and at work, and I enjoy looking at ...