So is that a YOUR confirmation that the
> zig zag construction at say (eg Sacsayhuaman) is
> just and accident of nature?
> Don't remember ever saying anything about the
> walls being an accident of nature. As far as I
> know, nature doesn't have accidents. How could
> So you are fine with wall construction out of
> random loose fitting stones (no accident of nature
> there), but you split your sides at the idea of
> constructing walls out of natural limestone which
> has precipitated out into a type of close-fitting
> The limestone in the walls is a form of tufa
> bordering on travertine and which is 3.5 to 4.0 on
> the Moh's scale.
> Here's a little excerpt from the building of
> Canterbury Cathedral.
> The use of tufa as a building stone can be
> traced back to the ancient Greeks who called the
> stone poros because of its porous nature.
> Tufa is formed by the re-deposition of calcium
> carbonate from ground waters. Rain falling on the
> North Downs, or on outcrops of the Greensand
> Ridge, has slowly percolated through the chalk or
> calcareous sandstone respectively, dissolving
> carbonate on its way. When the waters re-emerge at
> the spring-line, they are often saturated with
> carbonates ready to be precipitated out of
> solution (much like the process that forms
> stalactites and stalagmites).
> The spring location is rich in vegetation and the
> carbonate is precipitated around the mud and
> organic matter. Once the vegetation has decayed
> and the tufa has been left to ‘dry out’ it
> becomes literally as hard as stone.
> The stone is very porous and its colour will
> depend on the nature and concentration of
> impurities in the precipitate but is commonly
> grey-brown after weathering.
> In its wet state the rock is extremely easy to
> carve and shape and has the distinct advantage of
> hardness and durability once it has ‘dried
> Tufa deposits were once widespread in Kent but
> were quickly seized upon by the Norman builders
> because of their availability and utility.
> Similar tufaceous deposits were known from
> Northern France and it has been suggested that
> some of this stone in the cathedral may have been
> brought over from the continent. Tufa in a
> building wall is often seen as an indication of
> Norman masonry (unless re-used). By the end of the
> Norman period tufa reserves, it is thought, were
> all but exhausted in Kent.
> Much of the tufa used in Canterbury Cathedral may
> have come from the terraces of the River Stour and
> therefore derived from the chalk spring waters.
> The numerous large holes give tufa a
> characteristic lightness in weight, which make it
> an ideal building stone where weight restrictions
> were a consideration.
> It is rarely an attractive stone as the irregular
> blocks tend to be roughly cut. It has therefore
> often provided an essential, but hidden, function
> in reducing the weight of the stone fabric."
> The blocks in the Wall have been slightly trimmed
> and positioned.
> Some of those at the Water Temple where the spring
> water still splashes over them may still be in the
> process of lithification. Take the water away and
> the process stops.
> No magic, no ancient technology, no geopolymer, no
> mystery. Just the technology of that time in
> The previous image is sandstone, not volcanic
> tuff. You may not believe it to be, but so what?
> Tufa can also precipitate out in a similar manner.
> I could show you images of the process but I've
> gathered that you don't like "pretty pictures."
> Anyway, thanks for the insults.
> Way to go.
> Get back to me when you've proven that
> Sacsayhuaman is a geopolymer construction.
Very Interesting . Thank you.