Mineral Guide > Precious Stones > Diamond gem stone and Corundum

Diamond gem stone and Corundum

Diamond gem stone and CorundumThe Diamond is generally conceded to be the most beautiful, as it is the most important, of precious stones. While other stones at times exceed it in value, weight for weight, in total importance as an article of commerce other gems are hardly to be compared with it.

Out of thirteen and one-half millions of dollars' worth of precious stones imported into the United States in one year, twelve million dollars' worth were diamonds. Not all this amount was employed for jewelry, since there is a large utilization of the stone for industrial purposes; but even for jewelry the diamond has a largely preponderating use. Its points of superiority are its hardness, high refractive powers, and, hence, play of colors, its transparency, and its luster. In all these qualities it excels any other known mineral. Hence, when, in addition to these, it exhibits different body colors, as is sometimes the case, no other gem can equal it in value.

Usually the diamond is colorless or white, although shades of yellow are also common. It is also known in shades of red, green, and blue, and in brown and black. The two latter are rarely transparent and grade into the varieties known as bort and carbonado, which have no value as gems but are highly important for industrial purposes.

In composition the diamond is pure carbon, thus not differing chemically from graphite or such forms of carbon as lamp-black, bone-black, etc. It is crystallized, but this can be said of graphite as well. Why carbon should assume the form of diamond in one case and graphite in another, as well as being amorphous in other occurrences, is not known. Such behavior of a substance is known as dimorphism, and numerous illustrations of it are to be found in nature.

Black Diamond Carbonado picture
Bort picture
Cut Ruby picture
Cut Sapphire picture
Diamond in Matrix picture
Diamond picture
Ruby Crystal picture
Sapphire Crystal picture
Spinel Crystal Balas Ruby picture
Spinel Crystal Rubicelle picture