There have been a series of gold rushes in the surrounding region since the original one, including a large hard-rock one in the upper Bridge River Country which began in the 1880s and 1890s but had its peak from the 1930s to the 1950s, focussed on two main mining towns at Bralorne and adjacent Pioneer Mine and that area's main base town of Gold Bridge. Gold mining and prospecting continues in the area to this day, as do prospects for copper, silver and nephrite jade, though not to the same extent. Until the discovery of even larger deposits of jade near Cassiar, the Lillooet area was the world's largest source of the nephrite form of jade. Unknown tonnes were exported to China before government assayers discovered the nature of the "black rocks" that the Chinese miners found so interesting.