Colour Change Statement Note

Bill Hanneman · **Posted:** Thu Jul 08, 2010 12:21 pm

Quote:

A view through a Chelsea filter can cause various emeralds to become color change stones, yet we know they are not classified as such.

Strictly speaking, ALL gemstones are "color change or color shift".
When one changes the "color" (compsition) of the light source, the eye will note a change in its apparent color. (All amethysts are color "change or shift".It's just a matter of how much the color changes or shifts and the eyesight of the observer.

Quote:

Filters should not of neccessity be the arbiter for the C-chg call. A pocket torch is still $1 and the eyeball & brain the judge.

Without recognized standards of lighting and definitions of color, as well as a system of quantitative measurements, this entire subject is can never be resolved. It will always remain subjective—exactly like the vendors of such material want. Without standards, everyone's opinion is equally valid.

ROM · **Posted:** Thu Jul 08, 2010 1:29 pm

Bill Hanneman wrote:

Without standards, everyone's opinion is equally valid.

Especially on the internet! :lol:

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