Illinois State Monument - Missionary Ridge EarthCache

The Illinois Monument on Missionary Ridge commemorates the troops from Illinois who fought in the Battle of Missionary Ridge on November 25, 1863. This battle was a pivotal part of the Chattanooga Campaign, during which Union forces, led by Major General Ulysses S. Grant, launched a decisive attack against the Confederate Army of Tennessee. The Union's successful assault forced the Confederate forces to retreat into Georgia, marking a significant turning point in the Civil War and opening the path for the Union advance into the Deep South.

The Illinois State Monument on Missionary Ridge is crafted from Barre Granite, which is quarried in Barre, Vermont. This granite, part of the Devonian aged Barre Plutonic Suite, was formed around 370 million years ago during the Acadian Orogeny which was a period of mountain building events triggered by the collision of continental plates. The magma that crystallized into Barre Granite intruded into older metamorphic rocks, cooling slowly beneath the Earth's surface. This slow cooling process allowed for the development of a fine grained texture, characterized by small, interlocking mineral crystals. The result is a smooth, polished finish that enhances the granite's durability. Barre Grey Granite is notably resistant to heat, scratches, and stains, contributing to its popularity as a highly sought-after building material.

One other thing that is important to mention is that Barre Granite comes in three grades which are distinguished by color and grain consistency and include: light gray, medium gray, and dark blue-gray. The light and medium gray granites are extracted from the Smith Quarry, while the dark blue-gray variety is sourced from the Adam-Pirie Quarry. The dark blue-gray granite is the most distinctive among the three; it has the finest grain, achieves the highest polish, and is preferred for intricate shape carving. In comparison, medium gray granite is about 10 percent more expensive than light gray, and dark blue-gray is about 10 percent more costly than medium gray (light

1. Describe the color, texture, and grain size of the stone. Barre Granite may occasionally include xenoliths (fragments of rock trapped within the granite) as well as veins or pronounced flow features. Are you able to see any such discrepancies?
2. Based on your observations, what grade of Barre Granite was used to construct the Illinois State Monument?
3. Upload a photo with the Illinois State Monument. You don't have to be in the photo, though it is strongly encouraged.