Ken wrote:

> P.S. I checked a list a couple of hours ago that listed the ior values of over
> 170 different materials and not one of those listed was a common metal type.
> All were related in some way to crystaline structures and materials. i.e.
> quartz, glass, silicon carbide, salt, etc...

Depends on the literature. Long ago (when I was doing optics
in waveguides) we had tables with the IOR of copper, silicon,
aluminum etc.
It is relevant to know them e.g. for microscopic inspection
of ICs (the layers there are sometimes so thin that metals
have to be considered transparent).

AFAIK most of them have rather high IORs (I remember values about 
3 .. 4 for silicon) with even higher imaginary parts (which
are *very* relevant). The dispersion is also much higher than
for ordinary transparent media (many semiconductors are almost
transparent in the near IR).

Fresnels formulas gave pretty realistic colors for them using
a simple RGB model with the central wavelengths of the three colors.

Whilst this might be useless for raytracing metals, it might help
for stuff with similar behavios but much smaller imaginary part,
e.g. eosine (which is red in transmitted (and therefore diffusely
reflected) light, but green in properly reflected light (i.e.
"reflection","phong", and "specular" in POV).

Ralf

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