Diamond with darker brilliance

[kimf79]

What makes a diamond have a kind of darker brilliance, almost like a silvery or metallic sparkle? Does anyone know what I am talking about? Thanks!

 

[kenny]

Environment and lighting dramatically changes how diamonds look.

What you describe may be the result of a dark ceiling with spotlighting.

 

[Diamond Explorer]

The phenomena you are asking about could come from a variety of diamond's optical properties.

I have seen a few diamonds that look more "silvery" than your average diamond. I believe this probably has to do with the trace color of the diamond. Grey is sometimes the primary body tone, and diamonds with a touch of grey can look metallic to me in some lights. Perhaps this factor could cause the effect you are asking about.