Gold dazzles at refurbished Perth Mint

The biggest, heaviest and most valuable coin in the world is the centrepiece of a new permanent exhibition at the refurbished Perth Mint.

The colossal coin is one tonne of 99.99 per cent pure gold, worth more than $50 million.

Measuring 80 centimetres in diameter and more than 12cm deep, it depicts a red kangaroo surrounded by rays of sunlight.

And it sits atop its very own vault, which swallows it up each night when the mint closes.

West Australian Premier Colin Barnett said the coin would be a big drawcard for the Mint, which has undergone a $5.5 million redevelopment in two stages, the biggest revamp it has had since it was founded 115 years ago.

Mr Barnett said he expected visitor numbers, which already nudge 80,000 a year, would rise dramatically.

The coin was recently exhibited around the world and has increased already strong sales of bullion coins from the Mint.

"It achieved its objective - we are selling more gold bullion coins," chief executive Ed Harbuz said.

Also on display at the mint are massive gold nuggets, including the world's second biggest, Newmont's Normandy nugget.

Perth Mint was established as a branch of Britain's Royal Mint in 1899.

Its primary functions of refining gold from WA's eastern goldfields and striking gold coinage continues today but at its refinery near Perth Airport, with precious metal coins struck onsite at the Mint.

The Mint also issues Australia's official bullion and commemorative coins.

In 2012/13, it refined more than 300 tonnes of precious metals, reported close to $3 billion worth of holdings in its depository, and sold 4.3 million gold, silver and platinum coins.

It is one of only four mints in the world that produces bullion coins.