Seeing the color changes

[colorchange]

Hi everybody,

I have noticed that some people just do not see the red in alexandrite. You show them a fine alexandrite, they will see it as green under daylight and black under artificial light instead of red.

Do some here have an idea of why and how much peoplehave this flaw ?

C.C.

 

[JulieN]

color blind

after doing some reading. some 7% of males have red-green colorblindness.

 

[colorchange]

Thanks for your answer but that''s not what I''m talking about.

I’m talking of people who seem to see colors very well (they can see very well the shades of a ruby, and of course make a difference between green and red).
They just don’t see the red of alexandrites !
If shown with a bluish green to purple alexandrite they will recognize the bluish green but see an extinct light blue instead of the violet. But shown with a violet sapphire they see it as violet !

 

[RockDoc]

All the advanced gemological groups and most of the appraisal trade groups, REQUIRE color vision testing.

Everyone in the trade should have this done every few years. But unfortunately, if a person isn''t required to have this done, they generally don''t.

AGS requires it every two years if you''re over the age of 50. ISA requires this, AGA requires this and I believe NAJA and ASA requires this of their credentialed members. I''m not sure about the requirement in the various groups for non credentialed, affiliate or other levels of membership.

If someone DOES have a color deficency for a particular hue, many times it can be corrected by getting contacts with a certain coloring in the lens.

What I find strange is this not being a requirement to take gemological courses, before a student is enrolled.

I can''t imagine how "depressing" this might be for a student who spend thousands on a gemological education only to find out that for evaluating the color of colored stones that they are not able to do it accurately, after the $$$ and time are spent.

Consumers seeking the advice from appraisers should definately ask for verification that they''ve been tested, the result, and the date of the last test, when "appraising the appraiser".


Rockdoc

 

[Cehrabehra]

Date: 1/26/2007 1:05:03 PM
Author: RockDoc
All the advanced gemological groups and most of the appraisal trade groups, REQUIRE color vision testing.

Everyone in the trade should have this done every few years. But unfortunately, if a person isn''t required to have this done, they generally don''t.

AGS requires it every two years if you''re over the age of 50. ISA requires this, AGA requires this and I believe NAJA and ASA requires this of their credentialed members. I''m not sure about the requirement in the various groups for non credentialed, affiliate or other levels of membership.

If someone DOES have a color deficency for a particular hue, many times it can be corrected by getting contacts with a certain coloring in the lens.

What I find strange is this not being a requirement to take gemological courses, before a student is enrolled.

I can''t imagine how ''depressing'' this might be for a student who spend thousands on a gemological education only to find out that for evaluating the color of colored stones that they are not able to do it accurately, after the $$$ and time are spent.

Consumers seeking the advice from appraisers should definately ask for verification that they''ve been tested, the result, and the date of the last test, when ''appraising the appraiser''.


Rockdoc

wow, thanks rockdoc! I''m gonna stash that under "things I never would have thought to ask"!!