earthstory:Rough star sapphire (or is it ruby?)Both sapphire and ruby are the same mineral, corundum
earthstory:Rough star sapphire (or is it ruby?)Both sapphire and ruby are the same mineral, corundum, a mixture of aluminium and oxygen so simple that it has turned up in the most primitive meteorites, crystallised directly out of the emanations of the exploding supernova that scientists think may have triggered the collapse of a certain cloud of interstellar gas that later formed our Solar System. The only difference lies in the trace impurity that imparts the colour by selectovely absorbing wavelengths of light so that we perceive the residual colour: chromium in the case of ruby, iron and titanium for blue sapphire, and varying valencies (see http://on.fb.me/1I4XWKt for an explanation) of iron for most of the other colours (green, yellow etc). Keep reading -- source link