Metamorphic Rocks

Gray Marble

Marble is made when fairly pure limestone, a sedimentary rock containing the mineral calcite, is changed by great heat and pressure, over millions of years, deep under the Earth's surface, and recrystallized into a metamorphic rock. Marble occurs in many colors - white, pink, gray, red, yellow or black, depending on the amounts of the various minerals in it. Marble is made mostly from calcite which may contain graphite, pyrite, dolomite, quartz, mica and other minerals which produce the mottled or patched colors. It has a sparkly lustre.

Green Marble

Grain size can vary from fine to very coarse. Crystals are usually very fine calcite crystals, with some larger olivine crystals.

Marbles will effervesce (fizz) in weak acids due to the presence of calcite.

Olivine Marble

Any fossils originally present in the limestone were lost during the metamorphic recrystallization.

Many buildings and sculptures in Europe are made of marble, since it weathers well and retains a beautiful shine.