On your way up the Skyline trail, just a short distance from the Chimney, catch your breath and enjoy the views of Lake Lure and Hickory Nut Gorge from the Opera Box. When you enter this unique spot, you are covered by a rock overhang with a narrow horizontal opening that presents panoramic scenes of sky, water and trees while the wind and the birds provide the perfect soundtrack.

This splendid viewpoint was formed when a large block of Henderson Augen Gneiss (pronounced "nice") separated along its horizontal foliation plane and fell. Gneiss is the metamorphosed rock that makes up the entire valley including the massive cliffs in the Park. Originally, the Gneiss solidified from a molten magma to form a medium-grained rock. The "layering" or "banding" found here and the large white "augen" (grains of potassium feldspar) occurred in the rock much later during mountain building geologic periods when the rocks experienced elevated temperatures and pressures causing the Gneiss to be altered (metamorphosed).

The term augen is the German word for eye and is used in geology to describe eye- or elliptical-shaped minerals in a rock mass. In the Henderson Gneiss, the augen are composed of microcline. This augen texture is one of the most characteristic features of the Henderson Gneiss which distinguishes it from other rocks that have a similar mineralogical makeup. Some of the augen are quite large and have a shiny surface called a cleavage plane (a plane along which crystals break in accordance with their atomic structure).

The oval white "eyes," which somewhat resemble hickory nuts, are found in much of the rock exposed in Hickory Nut Gorge, the valley in which the Park is located. These "eyes" are said to have given the Gorge its name.

Page Tools