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This hornfels specimen from the Kittery Formation is an example of a contact metamorphic rock. The protolith (preexisting rock) was

Graphic granite is a feldspar-quartz intergrowth that is found only in pegmatites. It was commonly mined and locally known to

Basaltic magma intruded into a fracture in the pink granite of the Webhannet Pluton. Thus, the basalt is younger than

This granite block from the Deer Isle Pluton is an intrusive igneous rock consisting mainly of feldspar and quartz. Note

These two granite slabs from Hallowell Pluton are intrusive igneous rocks consisting primarily of feldspar and quartz. Note how their

This gneiss (pronounced “nice”) from the Mt. Ararat Formation, was originally a sedimentary rock that was subjected to high pressures

Gabbro is a dark, coarse-grained mafic igneous rock containing an abundance of magnesium and iron-bearing minerals such as pyroxene and

The contrasting dark and light layers reflect compositional differences in the limestone before its metamorphic transformation to marble. These layers

This rock is so full of inclusions, or ‘xenoliths’, that is resembles a conglomerate, a common sedimentary rock. It is,

The flat surfaces on this rock, from the Castine Formation, are natural fractures called joints. This is an example of