One time a sapphire was thrown as a pebble.

Sapphires were first discovered in the mid-19th century by gold explorers looking for gold in the Montana River.
Historically, commercial sapphire mining has been carried out in four key areas of southwest Montana, Pebble Belt (1865), Dry Cotton Creek (1889), Rock Creek (1892) and Yokogarsh (1895). in the upper Missouri River) there has been concentrated from these four deposits Only two sapphire production sites still produce sapphires. Below are green to blue rough crystals and faceted sapphires selected from the Creek deposits.