Rio Tinto diamond encrusted coins worth $1.8 million for sale in Australia

A $1.8 million coin trilogy boasting coloured diamonds found at Rio Tinto’s Argyle mine has been unveiled at the Perth Mint with international buyers already showing interest in the unique collection.

The Australian Trilogy is comprised of three one-kilogram coins struck from gold, platinum and rose gold, with each featuring a different native animal.

Each of the precious metals coins has either a pink, purple-pink or violet diamond, which were unearthed at Rio Tinto’s Argyle mine.

Each of them has either a pink, purple-pink or violet diamond, which were unearthed at Rio Tinto’s (ASX:RIO) Argyle mine in the east Kimberley region of Western Australia.

One of the coins, made 99.99% of gold, portrays two kookaburras on a wooden fence looking at a 0.47-carat round brilliant cut fancy deep purple-pink diamond.

The kangaroo coin, crafted from 99.95% pure platinum, depicts the marsupial in an outback plain with a 0.46-carat emerald-cut fancy dark grey-violet diamond.

And the 91.7% rose gold koala coin depicts the animal beneath a eucalyptus tree beside a 0.58-carat emerald-cut fancy intense pink diamond.

The Perth Mint will only ever release one of The Australian Trilogy 2017 Collection, Rio Tinto said in a statement.

The company’s Argyle mine generates more than 90% of the world's pink diamonds, yet less than 0.1% of all the rocks found there are pink.

The 2016 Kimberley Treasure coin, valued at $1 million, sold to an international buyer within 48 hours.