How to Identify Different Rock Types for Carving

Rock carving has been part of different cultures around the world.

Carving into rock used to be a way for people to communicate with each other, tell stories and maintain history. Now rock carving is a sculptural art form. There are three types of rocks available on earth: igneous, sedimentary and metamorphic. Igneous rock forms from magma deep within the earth and is pushed up through older, solid rock. Sedimentary rock forms from the eroded particles of other rocks blending with dead plant and animal forms and forming a solid mass. Metamorphic rock forms when sedimentary rocks undergo natural, chemical changes. All of these produce carvable rocks that sculptors can use.

Instructions

1. Determine whether the rock is igneous, sedimentary or metamorphic. Igneous rocks are extremely hard, sedimentary rocks are medium to soft with earth tones, and metamorphic rocks are medium to very soft with a variety of colors.

2. Feel the hardness of the rock. Granite, an igneous rock, is very hard, but still can be carved. Limestone and sandstone, both sedimentary rocks, are medium to soft. Metamorphic rocks like alabaster and soapstone are soft, making them easy to carve and add textured details. Marble is also metamorphic, but considered to be of medium hardness, and requires tools for carving.

3. Observe the rock's colors. Granite comes in grays, blacks, blues and browns. Limestone and sandstone each come in buff, grays, reds and browns. Metamorphic rocks like alabaster, marble and soapstone range from translucent white to dark black.

Tips & Warnings

• Colorado or Italian Carrara marble and limestone from central Indiana are easy to carve, according to Stone Shaper.

• Granite, sandstone and soapstone should only be carved while wearing a respirator.

References

• The Sculpture Studio: Stone Types
• Stone Shaper: Stone Sculptures