How the hell could it be the first they found? What did they do to invent the portal gun prior to getting moon rock? It makes no sense to think of it as either the first or only conductive substance. The most common perhaps, but not the only. I mean if the tubes with the moon rock were shut down, then what was the current aperture science walls coated with? Like I said, it doesn't add up.
That was a bloody stupid typo. I meant to write
best, not first. Would not make sense, seeing that the first portal device (that Ghostbuster Proton Pack look-a-like) shows up in the 50s. After that, something in lunar rock was found to be the way best conductor, so they used that. Makes sense to me.