Usually associated with an intense blue colour, Lapis Lazuli has historically been a semi-precious stone in jewellery. In addition, it has been used in many other ways such as being ground into a fine dust to create a rare pigment named "ultramarine" which was often used by renowned artists for their more important works.
As it has been used in jewellery for an extremely long time and remains a popular choice, it is quite likely Lapis Lazuli will continue to retain a presence in jewellery for a long time to come.
Colour
While it is true that Lapis Lazuli is generally an intense blue gemstone, it often deviates slightly towards lighter blue or green, though it is never fully green.
In addition, it is not a 'solid' blue colour – generally there is a certain amount of speckles that can be observed. These speckles tend to take on a grey appearance which stands out on the blue stone's surface. This is caused by the stone's composition: while it is most prominently composed of the mineral lazurite, it also contains other components such as pyrite or calcite.
The finest of Lapis Lazuli stones, however, can attain a near-perfect solid blue appearance. For these stones, it is generally best if they have no grey coloured spots. In contrast, a small presence of golden speckles is generally tolerated on these high quality stones.
Use
Lapis Lazuli, it is primarily used in jewellery. Primarily, it is cut into round shapes as opposed to angular ones. Thus, it is common to see this stone in a cabochon shape as well as oval shapes. Less common, but still accessible, are more elaborate shapes such as hearts or trillions. However, it can be used in other ways too. One practical use of it is to create a box – perhaps as a decorative storage place for jewellery. Other uses include vases and other decorative purposes.
One famous appearance of this gemstone is Tutankhamun's funerary mask where the eyebrows and eye surrounds were created of Lapis Lazuli.
Characteristics
As a stone, Lapis Lazuli is not quite as hard as other gemstones, ranging from 5 to 5.5 on the Mohs hardness scale, it is significantly less hard than a Sapphire, for example, which would be a 9 on the same scale. But this does not prohibit its use in the jewellery industry. Generally, it does not have a brilliant lustre even when polished – though its intense blue colour is a rather notable visual aspect of its own.
It should be noted that while it is suitable for jewellery, its (comparatively) lower hardness means it is best to be careful when handling these stones as they don't have a good resistance to forceful impacts and knocks.
Sources
Lapis Lazuli occurs in many areas of the world such as parts of South America (mainly Argentina), Canada, Europe and Italy. Its most abundant deposits, however, are located in Afghanistan. It is there that the finest Lapis Lazuli stones are produced.