Fresnel isn't for mirrors, but for stuff which looks like a mirror from the Side but not from the front. If you want a material with Fresnel, it would be helpfull to know what kind of material you have in mind - metal needs a different shader than Plastic does. 

And then things are getting complicated. You have reflections on a material that's not totally reflective. So, if you have any normal lights in the scene, you will need speculars too. If you have GI, the specular light should fit to the reflection used. 

Rendering engines like Luxrender or Blender's Cycles do have "Glossy" nodes, which handle reflection, speculars and diffuse - Poser does not. So if you want a glossy material with reflections, you need a reflection node, a diffuse node (either the one in the root shader or a seperate one) and a specular node, coupled to the reflection nodein a way that both do about the same, one for lights, the other for GI.

 

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

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