Even though the Sapphire is a prized gem, it is chemically identical to the abrasive on fine emery paper.
That is because a Sapphire, (as well as a Ruby), is composed of corundum. The difference
between a ruby and an abrasive is in the crystalline form.
The ancient Persians believed that the blue of the sky was the reflection of a giant Sapphire upon
which the earth rested. Kings and royalty wore Sapphire to protect them from harm. In addition, since the rays of a
Sapphire were supposed to kill poisonous snakes, they were thought to be proof against poison. The Sapphire, besides
protecting from harm, was supposed to attract the favor of the gods, while protecting the wearer from the envy of their
peers. The word Sapphire comes from the word "Sappheiros" which is Greek for "blue." By far the most common color for a
Sapphire is blue. However, corundum comes in many colors which range from nearly transparent
to opaque black.
In most gems inclusions reduce the value of a particular stone. However, with Sapphires, there are
some inclusions which increase the value because of what they do to light when it moves through the stone. There are
long, rod shaped inclusions known as Rutile needles cause some polished Sapphires to exhibit asterism, or the appearance
of a star of 4, 6, or even 12 rays that moves around the stone as it is rotated. These stars may be more or less pronounced
depending upon the concentration of Rutile needles in that particular stone. Another effect seen in Sapphires is called
"cats eye", where a band of bright color is reflected along the midline of the stone. This is rare, and so cats eye Sapphires
are somewhat more expensive.
Besides as a beautiful jewelry stone, Sapphires have value as abrasives. Since only diamonds are harder,
Sapphires can be used to wear down, or abrade, other materials. Emery paper and garnet paper are examples of the stones
being used in this manner. Most commercial Sapphires are man made, and the art is well advanced. Companies can create
Sapphires of varying sizes to provide uniform grit for abrasive uses. One of the more interesting uses for synthetic Sapphire
is the crystal of the Rolex® Submariner watch. Since the Sapphire is so hard, the crystal of a Submariner won't be
scratched by anything but a diamond.
Gwen's Glorious Gemstone Gallery
231 Lee Street