Peruvian rock cutting juice

[Getragdogleg]

I was watching a documentary about the intricate joints in the stones of Machu picchu and it was postulated that the builders knew of a plant extract that could soften rock so it could be shaped and then washed away after to leave a hard accurate joint.

looking at some of the amazing joints they managed to make I can see why this has been suggested.

is it possible that this is another bit of lost knowledge ?

http://tilakdutta.wordpress.com/2011/05/17/inca-st...