Choose the word which is different from the rest.

Shale
Slate
Marble
Gneiss E. Quartzite

The answer is marble.

Shale, slate, gneiss, and quartzite are all metamorphic rocks, which are formed when existing rocks are subjected to heat and pressure. Marble, on the other hand, is an igneous rock, which is formed when magma or lava cools and solidifies.

Shale is a fine-grained sedimentary rock that is composed of clay minerals. It is typically found in layered deposits, and it can be easily split into thin sheets. Slate is a metamorphic rock that is formed from shale. It is also a fine-grained rock, but it is much harder than shale. Slate is often used for roofing and flooring.

Gneiss is a metamorphic rock that is formed from granite. It is a coarse-grained rock that is composed of alternating bands of light and dark minerals. Gneiss is often used for building stone.

Quartzite is a metamorphic rock that is formed from quartz sandstone. It is a hard, dense rock that is composed of quartz crystals. Quartzite is often used for countertops and other decorative applications.