The perlite occurrence is located on the south side of Blackwater Creek, 6.5 kilometres south of Juskatla Inlet.

The area is underlain by a sequence of basalts, andesites and minor felsic flows, pyroclastics and interflow breccias of the Upper Oligocene to the Lower Pliocene Masset Formation. This unit forms a plateau volcanic sequence dipping gently to the northwest.

Medium grey to black perlite crops out for 85 metres along the roadcut immediately northeast of bridge Q9 over Blackwater Creek. The bed strikes north and dips 65 degrees east. Samples tested with a hand-held propane torch expanded to several times their volume (Geological Fieldwork 1989, page 486). A sample tested by CANMET exhibited the following characteristics (Geological Fieldwork 1990, pages 265 to 267): Per cent weight loss when heated to 800 degrees Celsius: 4.3 Softening temperature (degrees Celsius): 1240-1270 Density before heating to softening temp. (kg per cubic metres): 2370 Density after heating to softening temp. (kg per cubic metre): 450