Jurassic granodiorite, of the Jurassic to Tertiary Coast Plutonic Complex, was mined in five quarries at the turn of the century on the south-west end of Kelly Island (formerly Granite Island), west of Nelson Island.

Medium-grained granodiorite from all five quarries is similar in appearance but slightly darker than Nelson Island (092F 189) and Hardy Island (092F 425) stone, containing more biotite. In thin section, the rock is seen to be comprised of orthoclase, plagioclase, quartz, biotite and a few grains of green hornblende. Patches of pyrite less than 1 centimetre in size and a few black knots are visible on quarry faces.

The largest of the quarries is 110 metres long and has a face 12 metres high. There are potential reserves at all five quarries. Joints and fractures are irregular, striking northwest to northeast and dipping between 8 and 90 degrees. Large blocks are potentially available in areas where joints are widely spaced (greater than 1 metre). Physical properties are as follows (CANMET Report 452, p. 90):

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Specific gravity 2.681

Crushing strength (dry) (lbs/sq.in.) 35,144

Transverse strength (lbs/sq.in.) 3,521

Shearing strength (lbs/sq.in.) 2,756

These quarries were operated by West Coast Granite company in

the early 1900's. The granodiorite has been used as a foundation

stone in Canada and the United States and was used to construct the

Victoria Harbour seawall because of its durability and attractive

appearance. No production figures are available.

Adera Natural Stone Supplies Ltd. operates the quarry.

Granite Island Ltd. also operates a quarry on Granite Island.