For some reason this keeps getting passed over. King of the Americas, would you mind reading and responding to it? Architectural cramps and other artifacts made of "a unique copper-arsenic-nickel bronze alloy" exist at Puma Puncu and in other sites in the same region.
It follows logically that adzes, chisels, saws and other stone-cutting tools would have been made from that "unique alloy" as well. There is no need to speculate on advanced or "lost" technology, since we know for a fact that the builders of Puma Puncu employed metal tools of other kinds.
Notable features at Pumapunku are I-shaped architectural cramps, which are composed of a unique copper-arsenic-nickel bronze alloy. These I-shaped cramps were also used on a section of canal found at the base of the Akapana pyramid at Tiwanaku. These cramps were used to hold the blocks comprising the walls and bottom of stone-lined canals that drain sunken courts. I-cramps of unknown composition were used to hold together the massive slabs that formed Pumapunku's four large platforms. In the south canal of the Pumapunku, the I-shaped cramps were cast in place. In sharp contrast, the cramps used at the Akapana canal were fashioned by the cold hammering of copper-arsenic-nickel bronze ingots. The unique copper-arsenic-nickel bronze alloy is also found in metal artifacts within the region between Tiwanaku and San Pedro de Atacama during the late Middle Horizon around 600-900.
--summarized from: Protzen, Jean-Pierre; Stella Nair, 1997, Who Taught the Inca Stonemasons Their Skills? A Comparison of Tiahuanaco and Inca Cut-Stone Masonry: The Journal of the Society of Architectural Historians. vol. 56, no. 2, pp. 146-167
Robinson, Eugene (1990). In Bolivia, Great Excavations; Tiwanaku Digs Unearthing New History of the New World, The Washington Post. Dec 11, 1990: d.01.
Lechtman, H.N., 1998, Architectural cramps at Tiwanaku: copper-arsenic-nickel bronze. In Metallurgica Andina: In Honour of Hans-Gert Bachmann and Robert Maddin, Deutsches, edited by T. Rehren, A. Hauptmann, and J. D. Muhly, pp. 77-92. Bergbau-Museum, Bochum, Germany.
Lechtman, H.N., 1997, El bronce arsenical y el Horizonte Medio. En Arqueología, antropología e historia en los Andes. in Homenaje a María Rostworowski, edited by R. Varón and J. Flores, pp. 153-186. Instituto de Estudios Peruanos, Lima.