Metamorphic Rock Classification

ROCK NAME TYPE PARENT ROCK CHARACTERISTICS

SLATE foliated shales and muds prominant splitting surfaces; crystals not visible

SCHIST foliated fine grained rocks micaceous minerals visible, often including larger crystals of other metamorphic minersla such as garnet; foliation often crinkled or wavy

GNEISS foliated coarse grained rocks dark and light bands or layers of ferromagnesian and non-ferromagnesian silicate minerals

QUARTZITE non-foliated sandstone interlocking almost fused quartz grains, little or no porosity

MARBLE non-foliated limestone interlocking, often coarse, calcite or dolomite crystals, little or no porosity

ROCK NAME	TYPE	PARENT ROCK	CHARACTERISTICS
SLATE	foliated	shales and muds	prominant splitting surfaces; crystals not visible
SCHIST	foliated	fine grained rocks	micaceous minerals visible, often including larger crystals of other metamorphic minersla such as garnet; foliation often crinkled or wavy
GNEISS	foliated	coarse grained rocks	dark and light bands or layers of ferromagnesian and non-ferromagnesian silicate minerals
QUARTZITE	non-foliated	sandstone	interlocking almost fused quartz grains, little or no porosity
MARBLE	non-foliated	limestone	interlocking, often coarse, calcite or dolomite crystals, little or no porosity

Contact metamorphic rocks are recrystallized and rarely show foliation. Shales baked by igneous contact form very hard fine-grained rocks called HORNFELS. Calcareous rocks (dirty limestones) when subject to contact metamorphism an alteration by hot fluids produce rocks called SKARNS.