Local Granites: A Brief Overview

Granites are a common type of igneous rock found in many parts of the world, including our local area. They are coarse-grained rock composed mainly of quartz and feldspars. Granites are formed when magma (molten rock) cools slowly beneath the Earth’s surface or through intense metamorphism of sedimentary rocks. The ages of the granites in the New England area vary; Barre Granite, which is from the area of Barre, Vermont, is Late Devonian in age (354-370 Mya) and has been a popular granite worldwide due to its uniformity of color. 

Sources of Local Granites

The granites in our region were formed through the complex history of the region. Some local granites were formed as magmas deep in the crust and others were formed through the metamorphism of sedimentary rocks (such as mudstones and sandstones) into various granites due to high temperature and high pressure conditions as they were buried deep in the Earth’s crust. 

Mines and Quarries

Several mines and quarries in our region extract granite for commercial use. These mines and quarries are located in areas where granite deposits are exposed or easily accessible. The granite extracted from these sites is used for various purposes, including construction, landscaping, and decorative applications. Not all granites in the area have properties that make them appropriate for memorials. For a granite to be good candidates for memorials they should be strong, erosion-resistant, and be able to show engraved designs and lettering clearly. 

Types of Local Granites

Local granites exhibit a range of colors and textures, depending on their mineral composition and geological history. Some common types of local granites include:

• Pink Granite: This type of granite is characterized by its pinkish hue, which is caused by the presence of potassium feldspar minerals. Mountain Rose granite is an example of this type of granite that is used in memorials. 
• Light Gray Granite: Gray granite is another common type, with a more neutral gray color resulting from the dominance of quartz and plagioclase feldspar minerals. Barre Gray granite is an example of this type of granite. 
• Dark Gray Granite: Dark gray granite that is of memorial quality is less common locally. A historical example is Quincy Granite, which was quarried in Quincy, MA. The granite is no longer quarried. 

Some Resources About Local Granite History

Vermont Granite Museum (https://www.vtgranitemuseum.org/) 

Quincy Quarry and Granite Workers Museum (http://www.quincyquarrymuseum.org/)