OPL Pocket Spectroscope$98.00
- Small size (2" x ½" in diameter) ideal for use in the field (sealed for protection from damage)
- Fixed slit (recessed for protection from damage)
- Fixed focus
- High-quality craftsmanship; made in England
The spectroscope is a relatively small instrument that analyzes light passing through a stone.
When all of the colors of the visible spectrum of light are present (red, orange, yellow, green, blue, indigo, and violet), a white light is visible. To understand the spectroscope, all you need to realize is that when white light travels though a gem material, one or more of the wavelengths that produce color are absorbed by the gem.
This is not something that we see with the naked eye, but if we could watch as light travels through a stone, if we could observe all the colors making up the white light as it enters, we would see that certain colors simply disappear as the light passes through it. This phenomenon—called selective absorption—provides a very useful clue to gem identity.
What the spectroscope does is enable us to see this phenomenon in many gems—to know what color has been absorbed—by producing a vertical black line or bar in the space where the spectral color that has disappeared should be. By seeing what has disappeared, what is missing from the full spectrum, we get a distinct spectral picture for that gem. This picture is its “characteristic absorption spectrum”—the pattern of color seen, and the placement of the black bars, that is characteristic for a particular gem.