Heatsink Top:
The copper fins are spaced about 1.0mm apart, using the stacked fin process (I believe this is the name given to it) which is so common these days. Essentially, each copper fin is interlocked to the adjacent fins to form an evenly spaced assembly. The copper fins are very thin, measuring no more than approximately 0.2mm thick.

Side A:
From the side, it is easy to see the peak of the internal prism base. The photo was taken from the side of the heatsink, so if its base were flat, you would be able to see all the way through. Instead, we can see the copper prism rise about 13mm into the fins of the AVC Z7H2403012 heatsink. At the very edges, the base comes to about 1mm thickness.

Side B:
The 70mm fan sits on an aluminum fan shroud which has been anodized and coloured to look like copper. If you look closely at the bottom center, you can see the edge of the copper prism which forms the base of the AVC Z7H2403012 heatsink. Spring clips mount over top of the heatsink to hold it firmly in the socket 478 heatsink retention frame.