Basic
Characteristics
When
we look at a gemstone what we see is light that has been altered
by the internal structure of the stone. Our eyes register different
colors according to the length of the light wave. The chemical and
structural attributes of a gemstone alters the light that passes
through it. Some light waves are refracted while others are absorbed
and the higher the angle of deflected light, the more spectacular
the sparkle. This is a result of how light enters, passes through,
and then exits the stone.
The
characteristic called luster describes the appearance of a stone’s
surface in reflected light.
Lusters
are described as follows:
Adamantine – Sparkling and brilliant like a diamond.
Greasy – A little less brilliant than diamond like ink or
a grease spot on paper.
Resinous – Less brilliant than greasy; the appearance of resin.
Pearly – Like mother-of-pearl on the interior of some seashells.
Silky – Has a ray of light like a piece of silk.
Vitreous – Glassy.
Waxy – Has a dull shine.
Dull or Matt – Like chalk.
Metallic – Has a sheen like metal. |