Updated: Apr 25, 2022
Evidence that other groups remove these massive stones from quarries and shaped them with nearly perfect joints includes the fact that the Inca used primarily copper and bronze tools. Archaeologists found considerable proof that they did work with these metals. However, there is no income evidence of working with iron. Instead, all evidence of iron occurred higher up in the mountains of Peru. The Andes were originally volcanoes, after all, and iron oxide occurred naturally throughout.
Only the hardness of iron, which is approximately 6 to 7 on the Mohs scale, could be sufficiently strong to perfectly shape the types of rocks found in the walls of that region. While the Inca used the software tools and did a lot of metalwork with gold and silver, they did not use iron tools. Attempting to carve or shape a granite, andesite, or basalt stone with a copper or bronze chisel would leave you with a broken or bent chisel and not much change to the stone. It is possible to break off pieces of a larger stone with a stone hammer, but it would take far too many hammers to make any significant change.
The Inca apparently used hematite, iron pyrite, and meteorite tools in some instances, but even these would not be hard enough to create the perfect shape of the stones. The intricacy of the Sacsayhuaman zigzag wall, temples, and even step-carved mountainsides could never have been created with the regularly used tools no matter how many people worked on them.
What is the end determination for these facts? All stylistic and architectural indications point to the Inca as the source of the Sacsayhuaman part of Cusco. However, the giant wall with its earthquake-proof sturdiness and impressive join work, could not have been created with the Inca tools or methods. Also, the massive stones were apparently moved from 35 kilometers away in a quarry site. Many people speculate how they could possibly transport such large and heavy stones. Wooden rollers seem like the most likely method. However, the trees in the area at that time did not grow large or straight enough to provide for the possibility.