A sandstone quarry is reported to be situated on the southern shore of Hornby Island, 1.6 kilometres to the southeast of the Hornby Island Wharf, where cliffs attain a height of about 10 metres. The exact location of the quarry is not known, but most of the sandstone cliffs on the southern shore are mapped as part of the Geoffrey Formation of the Nanaimo Group.

The weathered surface of the stone is buff colour. The unaltered stone is blue and much of it is very hard. It is abundant but pebbly streaks and the hard nature of the stone would make quarrying difficult.

A selected sample of the rock consisted of grains of orthoclase, plagioclase, quartz, volcanic rock and mica. The volcanic fragments often exceed 2 millimetres in diameter and the quartz and feldspar often exceed 1 millimetre. The feldspars are not greatly altered but the mineral grains are not closely appressed and there seems to be a large amount of cement.

Under the freezing test the stone showed serious disintegration on all edges and angles, and became very friable. Very little change was produced under the corrosion test. It absorbs water quickly and has a coefficient of saturation on the safe side of the danger line. The high quantity of magnesia is the most striking thing brought out by an analysis of the rock.

Hornby Island stone has been used to a very limited extent. The best example is the blue variety used in the Dodson block on Hastings Street in Vancouver. No production figures are available.