Ruby is a variety of the mineral corundum. This pink to blood-red coloured
gemstone is the most valuable stone from the corundum varieties.
It is the second hardest natural gem with the score 9.0 out of 10 on the Mohs
scale of mineral hardness. The only harder natural gem is diamond.
Colour is the most important factor of quality.
When the colour is orangy or more purplish, the quality of stone is lower.
On the other hand when the stone has vivid colour saturation
it is considered as the highest quality ruby.
Inclusion-free rubies are very rare. Usually, rubies have at least
some inclusions. When the stone has eye-visible inclusions and they affect
brilliance or transparency, price goes down dramatically.
Symbolism of rubies is connected mainly with their colour – colour of blood.
Rubies are very popular as an engagement rings beceause their color symbolises love
and passion. Ruby stone is the tradinional birthstone for July.