But after years of touring around the country - including as part of an exhibition at Wellington's Te Papa - it wasn't sold.
Dunbar Sloane snr put a lower estimation - between $50,000 and $70,000 - on the piece in a bid to attract buyers.
The piece was sold for $77,000 which was increased to $89,000 with the buyer's premium.
"There were a few people keen to buy it for $30,000...but you've got to be a fairly rich person to start bidding $89,000."
Mr Sloane said he was surprised the bidding went so high. "I thought it would be lucky to get $50,000-$55,000. I was delighted."
It was currently unknown who had purchased the piece.
Set on a wooden base of native kauri timber, the original pounamu boulder was excavated from Big Bay, South Westland.