He said generally piemontite was found in New Zealand only in the vicinity of the Matukituki Valley, near Wanaka.
It was deposited in various places in the Upper Clutha and near Arrowtown by glaciers hundreds of thousands of years ago.
It is harder than marble, almost as hard as greenstone and gets its colour from its manganese content.
The hand, holding a bronze flower, took Olley three months to carve with diamond and tungsten-tipped tools.
Olley, a self-taught professional sculptor for the past 19 years, said the piece, The Gentle Man, would be offered for sale at $60,000.
The exhibition is a fundraiser for Women’s Refuge, and has contributed over $1.5million to the organisation since it was first held in 1995.
Olley’s sculpture is one of about 100 pieces selected for the outdoor part of the exhibition.
