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level: Absorbtion spectrum and the spectroscope

Questions and Answers List

level questions: Absorbtion spectrum and the spectroscope

Question	Answer
What is the term used when the colouring elements of a gem material removes some wavelengths from the incident white light that enters the stone?	Selective absorption
The removal of light energy by selective absorption in gem materials happens at specific __________ ___________ in different stones	energy levels
What is the name of the colour spreading effect witnessed when the light passing through an object is refracted at different angles?	Dispersion
If you were to look at a ray of white light travelling through a glass prism, what would you see?	A rainbow spectrum
What light colour has the longest wavelength during dispersion and is therefore refracted least?	Red
What light colour has the shortest wavelength during dispersion and is therefore refracted most?	Violet
What is the name for the measurement of dispersion in a gem material defined by the numerical RI difference when determined between two different wavelengths, usually red and violet?	Dispersion value
What types of gem materials have a higher dispersion value, and therefore show the most fire?	Colourless
What type of relative dispersion does quartz, fluorite, topaz and corundum have?	Low
What type of relative dispersion does almandine garnet have?	Medium
What type of relative dispersion does zircon, diamond and demantoid garnet have?	High
What type of relative dispersion does synthetic moissanite have?	Very high
What is the name of the process where light passing through a minute opening is slightly spread out?	Diffraction
Diffraction can also occur when rays of light are reflected from very minute...	Grooves and particles
What is the term used to describe light being passed through a fine grid of parallel slits, causing the diffracted waves to produce a spread out spectrum?	Diffraction grating
What is the name of the tool used to look at the absorption spectrum of a gemstone?	Spectroscope
What do you need to use alongside the spectroscope to be able to get a reading?	Strong white light
What stone does this spectra picture show, a chromium spectrum with emission lines covering most of the violet, blue, green yellow and orange, with fine lines in blue and red?	Ruby
What stone does this spectra picture show, a chromium spectrum with emission lines covering most of the violet, blue, green yellow and orange, with fine lines in the red only?	Red spinel
What stone does this spectra picture show, an iron spectrum with emission lines covering yellow, with thinner bands in blue, green and orange?	Almandine garnet
What stone does this spectra picture show, an iron and titanium spectrum with a single emission line in the blue?	Sapphire
What stone does this spectra picture show, a chromium spectrum with weak emission lines from orange to yellow, and weak banding in the red?	Emerald
What stone does this spectra picture show, an iron spectrum with three distinct emission lines in the blue/green?	Peridot