Sapphire, also known as Lapis Lazuli, is a precious gem, a variety of the mineral corundum, which together with ruby, diamond and emerald, is one of the four most important precious stones in the world. Its term comes from the Greek Sappheiros (blue stone), and from the Hebrew Sappir (the most beautiful).
From a chemical point of view, sapphire is an aluminum oxide (Al2O3), with small amounts of iron and titanium (these two elements give it its characteristic blue). The presence of impurities (other chemical elements) in the structure is responsible for the color and the different gemological varieties.
The authentic sapphire is deep blue in color, it can also be found in other shades, except red, because the red variety of corundum is Ruby. The other colorations are known as "fancy sapphires"; among them are the white sapphire, which is colorless and transparent, the yellow sapphire or eastern topaz, the pink sapphire, purple sapphire, green sapphire and orange sapphire.
In general, sapphire is a durable mineral, it has a great hardness (9 on the Mohs scale), followed after diamond. Although its refractive effect does not reach that of the latter, it surpasses that of other precious stones. Sapphire has a hard and smooth texture, conchoid fracture, and a vitreous luster, although in some cases it is silky.
The crystals are almost never present in a pronounced shape, many times they are similar to the hexagonal prism and triangular dodecahedron, other octagons and hemispherical, or imperfect or convex boulders on one side and flat on the other.
Corundum can be found in magmatic, metamorphic or sedimentary deposits, the latter being the most frequent way to find it in all localities. The best sapphires come from the deposits of Sri Lanka, India and Myanmar, there are other main sources such as Kampuchea, Thailand, Vietnam, Kenya, Tanzania, Madagascar, Australia and Montana (USA). They are also found in Cambodia, Malawi, China, Brazil, and Colombia.
Some blue sapphires suffer a phenomenon called asterism, which occurs when the crossing of cracks causes the appearance of a pattern similar to the six-pointed star in the stone; all of this is visible if it is shaped and polished into a cabochon or rounded dome. These star stones are rare but highly prized and are even more expensive than other sapphires.
This mineral has been used by ancient civilizations, it is the favorite stone of important kings and religious. Sapphire was considered especially magical by ancient people and inspired by the power to strengthen. In Christology it is considered as a crystal of money; stone helps attract things, but it also helps keep you calm.
Sapphire utilities include the manufacture of jewelry and abrasives, it is used in moving parts of watches, in scientific devices, in aesthetic orthodontics (brackets), among others.
