Knowing your stone.

There are three main groups of rock:

• Igneous or Magmatic

• Sedimentary

• Metamorphic

  Each of these types of rock are formed in different ways that determine what the rock is going to be.  For example:

Igneous or Magmatic Rock

  These types of rock are formed by a melting, cooling and crystallization process caused by the cooling and solidification of  magma.  These types of stones vary widely in patterns and color.  Of the three types of rocks, only igneous rocks are formed from melted material.  Igneous is derived from the Latin word ignis or fire.  Some examples of these rocks are: Granite-both Homogenous and Oriented. 

Sedimentary

  Sedimentary rocks are usually created by the breakdown of igneous rocks and preexisting debris. They tend to form in layers as small particles of other rocks or as the mineralized remains of dead animals and plants that have fused together over time. The remains of dead animals and plants occasionally become mineralized in sedimentary rock and are recognizable as fossils.  Sedimentary is derived from the Latin word sedimentum or a settling/intension to settle.  Some examples of sedimentary rock are: Limestone, Travertine, and Sandstone.

  Metamorphic

  Metamorphic rocks form when sedimentary or igneous rocks are altered by heat and pressure deep underground.  Through the metamorphic process, both igneous rocks and sedimentary rocks can change into metamorphic rocks, and a metamorphic rock can also change into other types of metamorphic rock.  Metamorphic is derived from the Greek words, meta-means to transition or change, and morphe or shape/form.  Some good examples of metamorphic rock are:  Marble, Slate and Granite, both Veined and Oriented.