Intermountain Region

The mining of stone is from several quarries located a few miles south of the town of Oakley, ID on the west flank of Middle Mountain.

This thinly bedded micaceous quartzite including the Elba quartzite is quarried for decorative use and is composed of quartzite and muscovite mica. A metamorphic rock created from the deformation of quartz-rich sandstone, it quickly became famous for its quarried thickness of less than one-half of an inch. This enabled one ton of the stone to cover many more square feet than other stone veneers on the market. This characteristic, along with its color and durability, makes it highly popular and it is shipped throughout the United States and overseas. A unique type of Oakley stone is the green micaceous quartzite seen on the front of many 20th century buildings in southern Idaho and northern Utah. The green color of this "Elba Quartzite" is given by chromium-bearing mica, fuchsite.

The best access to the National Forest portion is through Castle Rocks State Park. This is a fairly new state park was designated in 2003. From I-84 in Idaho, take the Sublett Road exit toward Malta. Turn left onto Sublett Road. Sublett Road becomes Jane Lane. Travel to 4th Street, turn left on to Main Street. Turn right onto Center Street. Turn left on Elba-Almo Road, then west 1.4 miles on 2800 S. (Big Cove Ranch Road)

The Almo Pluton hosts the spectacular granitic rock formations in City of Rocks National Reserve, Castle Rocks State Park, and the southern end of the Albion Mountain Division of the Sawtooth National Forest. Much of the geologic story resulted from moving plates and colliding continents pushing intrusive magma to the surface where it solidified. Older rocks are around 2.5 billion years old--part of the Archean Green Creek Complex--some of the oldest in the country, but none is visible within the park boundaries. Sea deposited, fused and cemented sandstones, from around 700 million years ago, make up the Elba Quartzite, which can be seen in small outcrops around the area.

The Almo Pluton, a granitic intrusion that formed around 27 million years ago, pushed its way up through overlying rocks and sediments, makes up most of the granite of the Castle Rocks area. Effective weathering and erosion in joints of the granite created the fairy-tale resistant formations that remain today.

The brown varnish, also known as desert varnish, is iron oxide leached from the water that stains the surface of the rock and creates a erosion protective layer. In places where the desert varnish has broken or chipped away, small hollows quickly weather out.

Take Highway 75 (Sawtooth Scenic Byway), near Ketchum , ID , head north until you come to the overlook. Drive south on Highway 75 from Stanley , ID.

This overlook offers panoramic views of the Sawtooth Mountains. It is due for reconstruction in the fall of 2007, but visitors can still see breathtaking views.

The Sawtooth Mountains are mostly composed of batholiths--the pink 44 million year old Sawtooth Batholith and the gray 70 to 90 million year old Idaho and Atlanta Batholiths.

Intense glaciation as recent at 14,000 years ago carved the rough Sawtooth Range and left glacial moraines now forested along the base of these mountains. There are also many lakes nestled within these moraines. The sawtooth appearance of the mountains is due to the pervasive vertical fracturing of the granite.

Redfish Lake Lodge is located 60 miles north of Sun Valley and 8 miles south of Stanley just off Highway 75.

Redfish Lake is a glacial lake that occupies a U-shaped, glacially-carved valley. The water is contained on the sides by lateral moraines and on the north end near the lodge by a terminal moraine. Redfish Lake lies on a platform of Pleistocene glacial sediment, rimmed by Pinedale-age moraines and flanked to northwest and southeast by Bull Lake-age moraines and outwash terraces. The prominent morainal ridges high above the lake to the northwest and southeast are similar to the large, outermost moraines marking major drainages farther south on the Sawtooth front, likely constructed during early or middle Wisconsin time. Due west of this location are similar moraines, merging with the large Redfish moraines but constructed by glaciers descending the Fishhook Creek drainage. Smaller, younger moraines mark the shores of the lake and areas upvalley, but, surprisingly, remain unstudied. Redfish Lake Moraine Research Natural Area encompasses a section of the large lateral moraine on the east side of Redfish Lake.