What is the range of wavelength that corresponds to visible light?
Visible light goes from 400nm (violet, more energetic) to 700nm (red, less energetic)
What are hue, tone and saturation?
Hue is the spectral color of a gem
Tone describes the relative darkness or lightness of a color
Saturation refers to the intensity of the hue (ie from gray to vivid)
What is the body color of a gem?
The body color is the color produced by selective absorption
What is selective absorption?
Selective absorption is a fenomena in which some wavelengths of white light passing through a gem are absorbed. The remaining wavelengths are are combined and interpreted as color
What determines the specific wavelengths absorbed by a gem during selective absorption?
The absorbed wavelentghs are determined by the chemistry and structure of gems
What chemical elements are typically responsible for the coloring of gems?
The chemical elements responsible for coloring of gems are typically transition metals
What’s the difference between idiochromatic and allochromatic gems?
In idiochromatic gems, the coloring elements are an essential part of their chemical structure
In allochromatic gems, the coloring elements are not an essential part of their chemical structure but are instead impurites
Why the same chemical elements can give two different colors to different gems?
The same element can give different colors because it is present in different atomic structures in different gems and so it interacts with lights differently
What is dispertion? How is it called in gems?
Dispertion is the fenomena in which light traversing a material is spread out in different spectral colors. This is due to the fact that each wavelength is refracted differently and so it bends with a slightly different angle
Dispertion is called fire in gems
How is the dipertion value calculated?
Dispertion value is calculated by measuring the refractive index of a gem using violet (431nm) and red (687nm) lights, since RI depends on the wavelength used
What is diffraction?
Diffraction is the spreading of light into the spectral colors when it passes through a minute opening. It is noticeable only when light is reflected from regula patterns
What is iridescence? What causes it?
Iridescence is a color or series of colors seen in a gem when it is moved in the light
It is caused by light interference due to diffraction from regular structural features within some gems
Who is a good bug?
You is!!!
