Identification of a fibrous mineral, two samples of which were retrieved from a small open pit at abandoned mine workings located 2.5 km west of Rowland Flat in the Barossa Valley, on the bank of the North Para River, was made using X-ray diffraction to determine the mineral group, and scanning electron microscopy to investigate the mineral fibre morphology and chemistry. The scans showed that the fibrous mineral is a member of the serpentine group, and it has tentatively been identified as asbestiform antigorite. A positive identification will require further study using transmission electron microscopy, to try to establish the mineral's crystal structure by means of selected area electron diffraction (SAED). Chrysotile asbestos (white asbestos) is widely regarded as the only significant asbestos mineral in the serpentine group, and is the dominant commercial form of asbestos used in the manufacture of asbestos products. Asbestiform antigorite, however, is uncommon, and information is not readily available from the mineralogical or medical literature on the properties or health effects of this form of serpentine mineral. Indeed, antigorite is not included in most definitions of asbestos for commercial or regulatory purposes. Past reports issued out of the Nofer Institute of Occupational Medicine, in Lodz, Poland, indicate that the fibrogenic, carcinogenic and mutagenic activity of fibrous antigorite is similar to the biological aggressiveness of crocidolite (riebeckite or blue asbestos). Fibrous antigorite has recently been identified as a potential health risk at Inco's Goro nickel project in New Caledonia. The local presence in the Mount Lofty Ranges of outcropping asbestiform mineral fibres of the type documented in this report, together with knowledge of the information gained from the Polish toxicology studies, indicate that careless exposure to this mineral occurrence must be regarded as having the same health implications as would exposure to an occurrence of crocidolite (amphibole asbestos; riebeckite).