Similar to sapphires, the ruby is also a mineral corundum, with a formula of aluminium oxide and chromium.

As hard as the sapphire, the ruby is among the hardest gemstones after the diamond. The chromium is what gives it its pink or red tint. Monetary values of rubies are primarily determined by their colour, applying the grading parameters of the four Cs. The  most valuable rubies are the brightest reds often labelled pidgeon blood rubies.

All natural rubies have inclusions and imperfections, which is why almost all rubies are treated in some way, with heat treatment being the most common method. Rubies of excellent quality which are completely untreated are therefore far more valuable.

The Mogok Valley in Burma has historically produced some of the world’s finest rubies. Today excellent quality rubies are sourced from Mozambique and Tanzania where their value is rising.