I also started out as a gold prospector.
The atom pattern of man-made vs natural is the same. Perhaps a bit generalized, but I'm not to bothered by those tiny differences since I can't measure/compare them myself.
It is nothing the general gemmologist will take into account either.
Take a look below for a feeling of what a gemmologist will look at:
Verneuil Synthetic Corundum: Dangerous Curves
Following the Silk Road: Rutile in Corundum
I think I see it out of a different perspective, and I sorta get confused I'm not sure I follow what you are talking about.
So I say in advance it may be possible misunderstandings here and there. :P
As for diamonds, they are nothing more then grinding media IMO. :P
I think they want to use the diamonds to conduct heat, which they willingly do?
I know why, diamond is brittle. But so is glass. If you ever have worked with Lexan it's more plastic like then glass.

It's used as bullet proof glass I want to recall.
Having diffuclt to grasp the whole context.
Rre they just generally talking about the polymorfs of carbon? (they would be correct in that case)
Another possiblity, they might be referring to using polycrystalline diamonds? They appear harder, but really aren't.
Diamonds hardness varies with different directions. That's why diamonds can grind/polish diamonds.
Polycrystalline diamonds are sorta like a piece of sugar (those for coffee) several diamond grains form a mass.
The orientation of the grains differ, making it a more aggressive grinding media. It appears harder.
I know this from my own experience, since I use synthetic diamond as a grinding media for my gems I cut.
If you want to read up on diamonds in general, try this:
http://www.gemologyproject.com/wiki/index.php?title=Diamond
Suprinsingly up to date as well.
I am also not sure what you mean with "cubic"?
If you are referring to Cubic Zirconia, an imitation of diamond. It's only supposed to look like diamond.
Already the SG will make sure you can "feel" it isn't likely a diamond. (if it is a loose stone)
Synthetic cubic zirconia - The Gemology Project