All gem stones, except those belonging to the cubic crystal system, not only bend the light rays, but also split them in two.
Some stones absorb certain wave lengths of light and allow others to pass.
The spectroscope is an instrument designed to show with a high degree of accuracy which wave lengths have been absorbed.
Its construction is fairly simple.
Inside a metal tube, three glass prisms are arranged.
At one end of the instrument is an adjustable slit to allow light to enter.
This slit can be opened and closed as required.
The built-in glass prisms are designed to split the white light into its constituent colors and if a light is placed near the slit a continuous color band made up of the spectrum can be observed.
Imagine that the gem zircon is placed between the light source and the spectroscope.
The lamp fight must now first pass through the zircon before reaching the spectroscope.
While passing through the stone, certain wave lengths of light are stopped.
No longer will the undisturbed continuous spectrum be seen.
Instead, it will look as if somebody had drawn a mass of straight pencil lines vertically across the rainbow-colored band.
This effect is known as the absorption spectrum; the lines are called absorption lines.
If sunlight were viewed through the spectroscope, it would not give an uninterrupted spectrum; its absorption lines are due to elements occur¬ring in the sun.
It therefore cannot be used as a light source with the instrument.
In the case of zircon, it is believed that traces of radioactive substances form the absorption line pattern.
This is so typical that it is unique to the gem stone.
It also demonstrates how invaluable is an examination by spectroscope for the identification of some gem stones.
No other stone will show an absorption spectrum like this one.
If such a spectrum is seen, the stone under test must certainly be a zircon.
Many other gems have typical absorption spectra.
In many cases, these absorption spectra also form a valuable guide as to the composition of minerals.
Various metals often cause dark bands, which vary in position according to the host mineral- hence their usefulness in identification.
The narrow, fixed lines that can be seen in the absorption spectra of light coming from the stars are caused by the vapor of elements.
These provide a valuable guidline to astronomers who seek to determine the composition of the stars.
Some stones absorb certain wave lengths of light and allow others to pass.
The spectroscope is an instrument designed to show with a high degree of accuracy which wave lengths have been absorbed.
Its construction is fairly simple.
Inside a metal tube, three glass prisms are arranged.
At one end of the instrument is an adjustable slit to allow light to enter.
This slit can be opened and closed as required.
The built-in glass prisms are designed to split the white light into its constituent colors and if a light is placed near the slit a continuous color band made up of the spectrum can be observed.
Imagine that the gem zircon is placed between the light source and the spectroscope.
The lamp fight must now first pass through the zircon before reaching the spectroscope.
While passing through the stone, certain wave lengths of light are stopped.
No longer will the undisturbed continuous spectrum be seen.
Instead, it will look as if somebody had drawn a mass of straight pencil lines vertically across the rainbow-colored band.
This effect is known as the absorption spectrum; the lines are called absorption lines.
If sunlight were viewed through the spectroscope, it would not give an uninterrupted spectrum; its absorption lines are due to elements occur¬ring in the sun.
It therefore cannot be used as a light source with the instrument.
In the case of zircon, it is believed that traces of radioactive substances form the absorption line pattern.
This is so typical that it is unique to the gem stone.
It also demonstrates how invaluable is an examination by spectroscope for the identification of some gem stones.
No other stone will show an absorption spectrum like this one.
If such a spectrum is seen, the stone under test must certainly be a zircon.
Many other gems have typical absorption spectra.
In many cases, these absorption spectra also form a valuable guide as to the composition of minerals.
Various metals often cause dark bands, which vary in position according to the host mineral- hence their usefulness in identification.
The narrow, fixed lines that can be seen in the absorption spectra of light coming from the stars are caused by the vapor of elements.
These provide a valuable guidline to astronomers who seek to determine the composition of the stars.
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