History
The area has been inhabited by man for more than 10,000 years. Like much of Nevada, it was covered by lakes and lush forests which were slowly drained and buried due to volcanic activity, climate change and geological uplift. Remnants of this wetter period are evident in the abundant petrified and opalized wood found everywhere. These fossils can range in size from small twigs to huge petrified logs, many 30-50 feet long.

In the southwestern portion of the valley lies the 'Last Supper Cave.' Its bones and artifacts have been carbon dated to 10,000 to 12,000 years.  Little is known about these early inhabitants. It is believed they were nomadic peoples following the game herds and seasonally occupied the caves surrounding the marshy valley. Petroglyphs carved in boulders near the area are thought to be created by the Piute or Ute people who populated the area in later times.  The abundant common opal and obsidian in the region made an excellent material for creating tools and weapons as shown by the numerous artifacts which are still found nearby.

There is evidence that Chinese were the first opal miners in North America, sending an expedition to mine the precious black opal perhaps 4,500 years ago. 

During the late 1800's and early 1900's a few specimens were collected by passing cowboys and sheep herders. These early examples were widely reported in the press and soon prospectors and opal enthusiasts found their way to this isolated valley. Opals were first mined commercially in the area around 1905 with the discovery of the rich deposits which became known as the Bonanza Mine.  Other early mining operations included the Rainbow Mine. Both are still in production today.