The Cononish gold mine and outbuildings were broken into sometime between Thursday, 28 May, and Monday.
Thieves cut padlocks and stole samples of stream sediment, which police confirmed contained no gold.
Officers said the culprits would have had to walk along a three-mile rough track in order to access the remote site. They appealed for anyone with information to come forward.
Police are investigating after thieves broke into a gold mine near Tyndrum.