Color change in diamond without losing luminosity? :-( Please Help

[p_photoshop]

Hi, I really appreciate if somebody can answer this question:
I have a diamond image, which obviously has different shades in it, it actually has dark, like dark brown shades, which i want to change to lighter smth like light yellow, i tried replace color, hue/sat//light but the effect is not realistic like an actual diamond looks, it is loosing its luminosity. i even tried with magic wand tool, by selecting each darker part and changing color, but it does'nt look realistic either. I would be very grately if somebody could help me with this. I m using Photoshop 7.0
Here is the image link i m editing:
ImageShack - Hosting ::
Thank You in advance.

 

[poliveira]

I'd like to help you, but the link is broken

 

[p_photoshop]

image link

Hi, Thank you so much for your reply.
here is the link:
ImageShack - Hosting :: r2064chd10kygalleryex0.jpg

alternative link: diamond ring - YourImageSpace - Free Image Hosting

I would greatly appreciate your help.

Thank You!

 

[poliveira]

Ok.
First select what you want to change. Use soft brush (I paint in white in an empty layer with hardness at 0%, then select that layer...)
Drop an adjustment layer Hue/saturation
Play with the settings (don't move the lightness too much)
Change the blending mode to soft light, pin light or ovelay and tweak as you like.
My 5 min work:

 

[salvadore]

Color chanage

Here is my take on it,
I used the variations command and then faded the results with a screen blend mode of about 30 percent