If i placed my videocard on a conductive material, is it dead?

It's not conductive material that's the problem, but any if any static charge was present when the card and material made contact and if that charge discharged through the card or, for example through your fingers if they made contact first.
Basically, the only way to know is to install the card and see if it works.
If you have installed the card and it's not working, go through the usual fault finding first before making any possibly false assumptions.