Specimen Ridge, el. 8574 feet (2,613.4 m) is an approximately 8.5 miles (13.7 km) ridge along the south rim of the Lamar Valley

Lamar River

The Lamar River is a tributary of the Yellowstone River, approximately 40 miles long, in northwestern Wyoming in the United States. The river is located entirely within Yellowstone National Park.-History:...

 in Yellowstone National Park

Yellowstone National Park

Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

. The ridge separates the Lamar Valley from Mirror Plateau. The ridge is oriented northwest to southeast from the Tower Junction area to Amethyst Mountain. The ridge is known for its abundance of amethyst

Amethyst

Amethyst is a violet variety of quartz often used in jewelry. The name comes from the Ancient Greek ἀ a- and μέθυστος methustos , a reference to the belief that the stone protected its owner from drunkenness; the ancient Greeks and Romans wore amethyst and made drinking vessels of it in the belief...

, opal

Opal

Opal is an amorphous form of silica related to quartz, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most...

 and petrified wood. It was referred to as Specimen Mountain by local miners and was probably named by prospectors well before 1870. The south side of the ridge is traversed by the 18.8 miles (30.3 km) Specimen Ridge Trail between Tower Junction and Soda Butte Creek

Soda Butte Creek

Soda Butte Creek is an approximately long major tributary of the Lamar River in Yellowstone National Park. It is named for an unusual geologic feature near its mouth. Soda Butte and the creek were named by A. Bart Henderson, a Cooke City miner, in 1870...

. The trail passes through the Petrified Forest and over the summit of Amethyst Mountain el. 9614 feet (2,930.3 m).