Gold - a most desirable noble metal

Gold is highly valued for its colour as well as for being malleable and ductile, and as a noble metal it is unreactive and doesn't rust, says Allan Blackman from AUT in ep 33 of Elemental.

The name gold comes from the Anglo Saxon word gold, but its chemical symbol Au comes from the Latin word aurum, meaning 'glow of sunrise.'

Gold is the most malleable and ductile metal which is why it is beloved of jewellers. Its high value is a function of both its beauty and rarity.

It is very unreactive, and so chemically aloof that it bonds with only one element - tellurium.

The term 'acid test' is the use of nitric acid to determine whether a metallic object is gold - gold won't dissolve, but other metals such as silver will.

Nanogold will turn fibres like wool a lustrous purple colour, says Professor Allan Blackman from AUT.

Go to this episode on rnz.co.nz for more details