|
SAPPHIRE.
|
227
|
||
|
|
|||
|
|
|||
|
|
|||
|
The
blue corundum is, however, often defective, having milky spots, white
lines, flaws, or nodules, all which must diminish its value.
Some of these become more beautiful if exposed to a strong reflected heat in a crucible full of cinders and clay.
The
celebrated English chemist Brewster, having perceived the great
refracting power of the blue corundum, recommended and used it
beneficially for microscopic lenses.
The price of sapphire is variable. Feuchtwanger gives the following table :
|
|||
|
|
|||
|
|
|||
|
|
|||