Sapphire
(from Hebrew: Sapir) is the non red variety of the mineral corundum,
an aluminium oxide (Al2O3). It can be found naturally or manufactured
in large crystal boules for varied applications, including infrared
optical components, watch faces, high-durability windows, and wafers
for the deposition of semiconductors such as GaN nanorods.The
mineral corundum consists of pure aluminium oxide. Trace amounts of
other elements such as iron, titanium and chromium give corundum their
blue, yellow, pink, purple, orange or greenish color. Sapphire includes
any gemstone quality varieties of the mineral corundum except the fully
saturated red variety, which is instead known as ruby.
Although blue is considered the normal color for sapphire, it is found in the full range of spectral colors as well as brown, colorless, grey and black. Those other than blue in color are considered fancy color sapphires.
According
to Rebbenu Bachya, and many English Bible translations, the word Sapir
in the verse Exodus 28:18 means Sapphire and was the stone on the Ephod
representing the tribe of Issachar. However, this is extremely disputed
as though it is true that the english word sapphire derives from the
Hebrew sapir (via Greek sapphiros), Sapphires were actually not really
known about before the Roman 
Empire
(and were initially considered to be forms of jacinth, rather than deserving
of a word to themselves), and prior to that time sapphiros referred
to blue gems in general. It is thought by scholars that the sapphire
of the Bible was actually lapis lazuli - which was frequently sent as
a gift between middle-eastern nations in Biblical times (Texas Natural
Science Center, 2006). There is a wide range of views among traditional
sources about which tribe the stone refers to.
