Sacsayhuaman stone wall close-up - photos

[mklotz]

The first picture features the somewhat famous twelve-angled stone in Peru. It is diorite, which is about 7 on the Mohs scale. Similar to quartz. It's generally accepted that copper and bronze tools were used to cut stone at this time but it's unlikely that either type of chisel could make a reasonable concave cut in such a hard material. There must be some kind of yet to be discovered grinding/flattening process involved with Incan construction work.

The Egyptians had the same problem - hard rock and copper/bronze tools. The unfinished obelisk...

https://en.wikipedia.org/wiki/Unfinished_obelisk

discovered near Aswan demonstrates their approach to the problem. Diorite bowling-ball sized stones were used as hammers to gradually chip away the hard granite.

The same process could have been used in Peru to form a hollow in the face of one of the stones, perhaps with some material harder than diorite. (Note that I'm not saying it was so.)

Also, I believe some diorite balls were found in situ at the quarry from which Machu Picchu stone was obtained.

There's good reason to believe that the construction of these ancient stone works was regarded as an act of worship and so the immense patience, skill and devotion of the builders is easier to understand.