Dark Blue Sapphire

This natural sapphire has a round shape and a dark blue colour. Its size is 4.80 mm and its weight is 0.50 carats. Its clarity is good, with no inclusions visible to the naked eye. This sapphire has been heat treated to improve its colour and durability. Its provenance is from Sri Lanka, a country renowned for the quality of its sapphires. Its irregular handcrafted shape gives it a unique and original look.

Under the name sapphire are known all corundum gemstones with the sole exception of the ruby red variant which is called ruby. However, the name sapphire is very common for blue gemstones, but this blue should not be understood as the colour of clear sky, but all shades of blue up to very dark blue and even black.

Sapphire is found in a wide range of colours and shades.

Sapphire is a mineral that occurs asAl2O3single crystals. The colour is determined by impurities such asFe2+,Fe3+,Cr3+,Ti4+ orV4+.

It has a hardness of 9 on the Mohs scale, after diamond.

The rocks where sapphires have been found are called pegmatites, which through erosion processes have been transported and deposited in alluvium in river beds. The most important sapphire-producing countries are Sri Lanka (formerly Ceylon), India, more recently the USA, Australia and Nigeria.