Sapphire vs. Alumina — What's the Difference?

Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al2O3) with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors.

Any of several forms of aluminum oxide, Al2O3, occurring naturally as corundum, in a hydrated form in bauxite, and with various impurities as ruby, sapphire, and emery, used in aluminum production and in abrasives, refractories, ceramics, and electrical insulation. Also called aluminum oxide.

A transparent precious stone, typically blue, which is a variety of corundum (aluminium oxide)

Aluminum oxide, especially when used in mining, material sciences or ceramics.

A small hummingbird with shining blue or violet colours in its plumage and a short tail.

One of the earths, consisting of two parts of aluminium and three of oxygen, Al2O3.

A clear hard variety of corundum used as a gemstone that is usually blue but may be any color except red.

Any of various forms of aluminum oxide occurring naturally as corundum

A corundum gem.

The blue color of a gem sapphire.

Made of or resembling a gem sapphire.

Having the color of a blue sapphire.

Of or relating to a 65th anniversary.

(countable) A clear deep blue variety of corundum, valued as a precious stone.

A white, yellow, or purple variety of corundum, either clear or translucent.

A deep blue colour.

(countable) Any hummingbird in the genera Hylocharis and Chlorestes, as well as the rufous-throated sapphire, which is now in the genus Amazilia.

Any of the butterflies in the southern Asian lycaenid genus Heliophorus or the African lycaenid genus Iolaus.

Of a deep blue colour.

Pertaining to a 45th year

Native alumina or aluminium sesquioxide, Al2O3; corundum; esp., the blue transparent variety of corundum, highly prized as a gem.

The color of the gem; bright blue.

Any humming bird of the genus Hylocharis, native of South America. The throat and breast are usually bright blue.

Of or resembling sapphire; sapphirine; blue.

A precious transparent stone of rich blue corundum valued as a gemstone

A transparent piece of sapphire that has been cut and polished and is valued as a precious gem

A light shade of blue

Having the color of a blue sapphire;