More on Metamorphic Rocks

Readers share their favorite metamorphic rocks.

An introduction to the third great class of rock types.

The major metamorphic rock types, from regional, contact and mechanical metamorphism.

A spectrum of metamorphic rocks presented in metamorphic order, the pelitic sequence and the basaltic sequence.

A look at this mineral product, which has gone from champ to chump in the 20th century.

A picture gallery of this extreme metamorphic rock.

Phyllite is between slate and schist in the spectrum of metamorphic rocks.

Porphyroblasts are distinctly large crystals in a metamorphic rock. Here are pictures of some of the minerals that form porphyroblasts.

A gallery of these interesting, important and sexy rocks.

Slate is a widely used low-grade metamorphic rock.

One of the Web's geo-geek treasures, Robert Reed's site has been "out there" since 1995 with fanciful and solid material about granite.

Skarns are what happens when limestones get stewed in silica juices—the process called metasomatism. Larry Meinert of Smith College has run this authoritative site since 1996.

Karl-Peter Kelber's Links for Mineralogists site has a big grab-bag of rock-related sites for all levels of users.