They were often incised with sacred patterns, which could be tribal insignia, or have other meanings, or tell stories. Riji are associated with water, spiritual powers and healing due to the luminous shimmering quality of their surfaces. Bardi equate the light reflecting off the shells to lightning flashes, which are prominent during the monsoon, and to lights flashing off the cheeks of the Rainbow Serpent, who is closely linked to water and rain.
One of the unique patterns used in the Kimberley region of Western Australia is a pattern of interlocking designs. The incised designs are highlighted with a mixture of ochre and Spinifex resin, which is rubbed into the grooves. Decorated and plain pearl shells are used for rain-making and magical purposes or for trade.
Riji were objects of great value and were traded with inland Aborigines along ancient trade routes over vast areas of the continent. They have been found at Yuendumu in the desert, south-eastern Arnhem Land, Queensland and South Australia.
Often plain pearl shells were decorated further along trade routes, far from their place of origin.
Aboriginal artists Aubrey Tigan and Butcher Joe Nangan created riji out of mother-of-pearl buttons and cloth. Artists still make Riji today in the Broome area. Some use the older, sacred patterns, while others choose to use more modern designs.
- Short St Gallery Archived 2007-09-27 at the Wayback Machine.
- Lawrence, K.; Kean, J.; Wood Conroy, D.; Tigan, Aubrey; Nangan, Butcher Joe (2008). "Cloth and shell: revealing the luminous": SASA Gallery, Adelaide Bank Festival of Arts, 28 February - 28 March: This Everything Water. Adelaide, South Australia: South Australian School of Art Gallery, University of South Australia. Retrieved 31 July 2016.