A US coin-turned-ring is one of the most unusual pieces at Gray's Auctioneers' sale on March 10.

The $5 dollar American eagle gold coin has been designed into a ring and set around with 1.5 carats of baguette and round cut diamonds in a yellow gold setting. This ring fits a 7.75 ring finger and is estimated to make $1,200-1,500. It is sure to have numismatists and jewellery investors intrigued.

Another interesting lot is a custom designed diamond cut dome ring, encrusted with 52 round brilliant cut diamonds in a yellow and white gold setting. Weighing 12 pennyweights, with 5.5 carats of diamonds, this is a striking piece of jewellery.

This $5 coin could make 300 times its face value

Not to be missed is lot 41, a classic engagement ring. It is formed of a two carat, round, brilliant cut diamond sitting atop a white and yellow gold ring. This is set with six more round brilliant cut diamonds and 28 tapered and straight cut diamonds, for another 1.5 carats. All the diamonds have SI2 clarity and are colour graded G. The size 7.25 ring has an estimate of $7,000-8,000.

The sale includes more than 150 lots of rings, bracelets, necklaces, brooches, coins and currency.