16 stone gold coin

The Royal Canadian Mint has unveiled the world's first 100 kilogram (220 lb) pure gold coin.

Listed as 99.999 per cent pure gold bullion, the new pizza-size coin is mainly a promotional product to give the mint a higher international profile. The 100-kilogram coin was conceived as a showpiece to promote the mint's new line of 99.999 per cent pure one ounce Gold Maple Leaf bullion coins.

That extra nine makes it slightly purer than the 99.99 per cent gold coins offered by competitors. After several interested buyers came forward, the mint decided to make a very limited quantity available for sale.

The coin, which has not been named yet, will be sold as a limited time offer and will be made to order so there'll be no inventory to carry or to melt down if there's unsold stock.

Since 1979, the mint has pioneered high-purity Maple Leaf bullion coins, selling about 20 million ounces of them around the world. But it acknowledges that it has lost some of its competitive edge, as mints in Australia, Austria, China and the United States push their own high-quality gold coins.

Bennet said the 100-kilogram and the one-ounce 99.999 per cent pure gold bullion coins help separate the mint from competitors.

Austria, in particular, has had success with its 100,000-euro gold coin, worth about C$153,000 (£75,000). The Austrian coin is 37 centimetres across and weighs 31 kilograms (68lbs).