Todd - I agree, always good to get more reference material in a thread. I'll see what I can dig up.Date: 10/14/2009 12:36:45 PM
Author: Todd Gray
Date: 10/14/2009 12:15:05 PM
Author: AshNZ
Are you annoyed at learning something new?
Ash
Actually, I'm excited. However I tend to learn better visually, can you post some examples which demonstrate the principles which you are attempting to get us to understand? The forum is not only about open discussion, but learning and teaching. Perhaps this is an opportunity for you to teach - but with a class full of people who think out loud and have lots of questions...
Edit: For starters (a good primer on Absorbtion - more to come on ray path length)
http://www.gemology.ru/3dbook/eng/crypted/1_03.htm#4
Color is generally of primary importance for gemstones, but most of diamonds are colorless or near colorless. Hence, diamonds are primarily valued for their scintillation, brilliance, and fire, which are determined by the three properties described above: reflection, refraction, and dispersion. To describe these properties in combination, the term brilliance is often used, which denotes the overall optical image of a diamond. One can say that a stone is characterized by brilliance and color.
Color of stone is a property determined by selective light absorption. The ideal diamond is absolutely colorless; however, an actual specimen always contains microimpurities and structural defects, which absorb a part of the light passing through the stone. For example, the yellow color, which is typical of most diamonds, appears in the specimens that mostly absorb the blue and green constituents of the light spectrum (Fig. . Rare colored diamonds has a different absorption character. Diamonds containing few color centers have a tint rather than a color. On the other hand, intense absorption affects the transparency of a stone, and dark stones are perceived as translucent.
The ultimate impression of a diamond is formed by reflection, refraction, dispersion, and absorption, which determine its : scintillation, brilliance, fire, and color.
Ash