Metamorphic Rock Classification

Metamorphic rock is classified by texture and composition. The texture can be foliated or nonfoliated.

Foliated metamorphic rock

Foliated metamorphic rocks appeared banded or layered. Foliated rocks can be ordered in terms of increasing metamorphism. In the chart below notice how each of the first three rocks become the parent rock for the next. In each of these it takes more heat and pressure to to move to the next level of metamorphism. This is called degree of metamorphism.

Nonfoliated metamorphic rock usually contains one mineral. It is uniform in texture.

Texture-Grain Size

Grain size is an important characteristic of texture. It ranges from very fine to coarse. The metamorphic rock classification chart below may help you make sense of the many different types of rock.

Classification of Metamorphic Rocks
Name of Rock	Parent Rock	Texture	Grain Size	Notes
Slate	Shale, mudstone, siltstone	Foliated	very fine	smooth dull surfaces
Phyllite	Slate		fine	glossy sheen
Schist	Phyllite		medium to coarse	micaceous minerals
Gneiss	Schist, granite, volcanic rocks		medium to coarse	mineral banding
Marble	limestone	Nonfoliated	medium to coarse	Interlocking calcite or dolomite grains
Quartzite	quartz sandstone		medium to coarse	fused quartz grains
Anthracite	bituminous coal		fine	black, shiny, organic rock

Metamorphic Rock Formation

Examples of Metamorphic Rocks

Metamorphic Rock Collections For Sale


Metamorphic Rock Collection For Sale $6.95	Igneous Rock Collection For Sale $6.95	Sedimentary Rock Collection For Sale $6.95

Rock and Mineral Collections

Fossil and Geologic Time Book Sets

Fossil Collections

Share this page:

What’s this?

Facebook Twitter

Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

Click on the HTML link code below.
Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.