The only exception to the rule is Country Tyrone which has a bit of everything - clay, basalt, gabbro, granite, schist ... to form a new type of rock called sedimentary rock.

There are three main types of rock — igneous, sedimentary and metamorphic ... with examples including phyllite, schist, quartzite and marble. Igneous and metamorphic rocks on Earth's surface ...

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 ...