Blue tourmaline with gray overtone - photos?

[mimi72]

This is for TL, LD and any others on this board with a sophisticated eye in blue/aqua/cupric/paraiba-like tourmaline.

I have read that these stones can have an undesirable gray overtone and am trying to educate myself on this. Of course, I am sure that seeing two gray-overtoned and non-gray-overtoned stones side by side is the best way, but I do not have access to this.

So, I don't know if this gray overtone is something that is photograph-able, but if anyone has pics that hint toward the effect, I'd like to see them.

Thanks!!

 

[chrono]

Colour grading of gemstones can be broken down as hue (green, blue, yellow, etc), tone (light, medium, dark, etc) and saturation (vividness or strength of colour). When a person says a stone is grayish, it means that the colour isn't saturated. Usually cold coloured stones like blue is said to show grayness while warm coloured stones like red is said to show a brown tint.

While the example in the link isn't a blue tourmaline (blue sapphire), the pictures show a desaturated stone all the way up to a very well saturated stone, side by side.
http://www.palagems.com/quality_4cs.htm#color
Blue sapphire 1 is considered to be grayish blue.
Blue sapphire 2 is considered to be a saturated blue (no gray).

 

[mimi72]

Ahhhh. I think I get it. Thanks Chrono, that was very helpful. I will try to find a similar example in tourmaline.

 

[VAgemguy]

Chrono, that web page is a great resource! Thanks for posting it.

 

[Enerchi]

Great webpage - thanks Chrono for posting that link, it was a great read

 

[T L]

This is for TL, LD and any others on this board with a sophisticated eye in blue/aqua/cupric/paraiba-like tourmaline.

I have read that these stones can have an undesirable gray overtone and am trying to educate myself on this. Of course, I am sure that seeing two gray-overtoned and non-gray-overtoned stones side by side is the best way, but I do not have access to this.

So, I don't know if this gray overtone is something that is photograph-able, but if anyone has pics that hint toward the effect, I'd like to see them.

Thanks!!

Unfortunately, that's really the best and only way as far as I'm concerned to see the effects of a modifier such as grey or brown, or even yellow which is sometimes an undesirable secondary hue in some gems like tsavorites, and spessartites.

You can look at photos side by side, but the best way to train your eye is to go to a large gem show with many fine and not so fine examples.