Too many colours?

We all perceive the world differently but we'll never know quite how other folk see the world - particularly in relation to actual colours. Most folk have three receptors in their eyes for colour recognition but if you're born with just one extra cone cell in your eye you can see 100 million more colours. How amazing would that be - how many colours would you be able to see in a rainbow; more than the standard seven? And how would it be if your job was to look through the spectral whats-it to determine the chemical composition of planets. Who knew that's how it was done? Yes, those colours on the Periodic Table are there for a reason ... each element has a different colour and if there are numerous elements "together" then viewing then with the help of a spectral whats-it will allow the colours to be seen separately.