$50,000 for 'Pink Terraces' rock

A painting of The Pink Terraces before Mt Tarawera erupted in 1886, and (inset) the rock being sold on Trade Me which is said to have been given to a geologist. Photo / Supplied

A chunk of rock claimed to be from what was once the eighth wonder of the world could be yours for $50,000.

But the 1.6kg rock, touted as a "genuine chunk" of the recently rediscovered Pink and White Terraces, comes with a serious "buyer beware" warning from an expert geologist, who says it cannot be verified as genuine.

The seller, listed as Aaron, is peddling the rock on Trade Me, with bidding closing today.

He says the rock was given to a geologist as a gift about 1860, 16 years before the terraces were buried in the Tarawera eruption, and had been "passed down through the generations".

"It was then gifted to my father in 1989 by the great-grandson of the geologist just before his death as they were great friends and my father was an amateur geologist (as am I)," he claimed in the Trade Me listing.

The chunk had been well looked after and given baths every five to 10 years to keep the silica hydrated, he said.

He credited advice passed down through the generations for the rock's good condition. "It was also always stored in a cool damp place in damp sacking as well."

Aaron, who described himself as a registered collector of Taonga Tuturu, told the Daily Post in Rotorua this week that he did not have any proof the item was genuine.

"I would love to meet someone who could authenticate it and put their name behind it. The actual rock matches the physical characteristics of the pink terraces perfectly, with the pink swirls in it that were known as the tattooed rock."

He was reluctantly selling the rock to cover "future medical costs" for his family.

But terraces expert Brad Scott, a volcano surveillance co-ordinator at the Institute of Geological and Nuclear Sciences (GNS), put an "enormous caveat" on the rock, which he said could have come from any hot spring.

"You sort of wonder how they managed to break it off and smuggle it out, as I would imagine the local Maori were quite protective of it. If you had 1000 people visiting daily and each one chipped a rock off, you wouldn't have much left of it after a while.

"But on the other hand, it certainly looks like a piece of hydrothermally fermented material. The real big challenge is that there are so few pieces around to confirm or deny to compare it to."

Rotorua Museum of Art and History director Greg McManus said the rock was a piece of silica that "could have come from anywhere".

"To be honest with you, anyone who buys it without authentication has got more money than sense. I doubt it will sell - I certainly won't be buying it."

Mr McManus was aware of only one piece that was authenticated, housed at Canterbury Museum.

Trade Me spokesman Paul Ford said if an item was legal, it could probably be sold on the auction site.

"We also have an extensive banned and restricted list, but chunks of rock are not covered.

"We are not geological experts so it is tricky for us to authenticate it, but our advice is that if people have doubts they should ask questions and if they are not satisfied with the answers from the seller, factor that into their decision to bid.

"You'd be mad not to ask questions if you were bidding a meaningful amount of money."