Copper Age (Calcolithich) How pure was the CU?

[Bentiron1946]

Last night on NOVA on PBS the had a program about the Great Sphinx of Giza and they had this sculptor in New England using copper tools to make a "new" nose for the sphinx. Well you know he had a nice little coal forge to heat the copper in to for it on a large rock anvil with a rock hammer stone. The problem I'm having is it looked like they were using pure extruded 3/4" copper rod, you know the kind you get from your local metal supply store. This stuff is about 99.9% pure and I was having a hard time watching them try and carve stone with pretty pure copper. From what I've read about the Copper Age(Calcolithic) the copper was pretty well not 99.9% pure but had lots of other stuff in it like arsenic, silver, gold, lead, you know whatever was in there with the ore. Sometimes in pretty go proportions too, so I'm thinking that perhaps they may have had anywhere from a near pure copper to a pretty good near bronze tool to work the stone with and that would sure beat the heck out the 99.9% stuff the New England sculptor was trying to use on the "new" nose for the sphinx. So do any you have an idea or suggestion about the "copper" tools used to carve the Great Sphinx of Giza?

[bigfootnampa]

I'd suspect that they might have been billets for flaking rather than chisels.  Copper is still a popular choice for stone knappers today as it is heavy and has a nice "dead blow" effect on stone!  As a cutting tool material though (as opposed to a percussive tool) it has poor potential.

[Bentiron1946]

They were forging them down to what looked like 3/8" points and then smacking them with wood mauls and the ends were just curling up. At the end of the "nose"  project they were using them to flake or chip off small points of limestone to refine the profile of the nose. The ancient examples of the chisels look pretty much like contemporary stone working chisels but not so the one the New England sculptor was making. I have seen examples of early Bronze Age hammers from Europe and they are similar to socket axes except of course  blunt so I was having somewhat of a hard time with them having the Egyptians using only rocks as hammers for forging out the chisels. In the past I have observed knappers at work with copper implements and they are capable of some very fine exotics with their use of copper points rather than the traditional bone and antler but I just don't know how the ancients would have applied this type of flaking technology to something as large as the Great Sphinx of Giza. At this same time they were building the Great Pyramid also so they were already accomplished stone workers. I think that they had a trick or two that we in the modern world are missing in the use of Calcolithic copper tooling.

[Bentiron1946]

Been doing some more reading about Calcolithic tools and found a analysis on some early copper tools from Ur and they had quite a range of metals in them. First off was Tin, less than 0.018% but a couple of tools had it up to almost 3%, then next was Arsenic, with anywhere from near trace to a high of 3.9%, Nickle was next with0.5% to 2%, next was Lead with near trace to 2.7% and finally was Iron in the for iron silicates or slag at 0.9%. This is for a total of 48 "copper" objects. If something similar holds true for the Egyptian masons chisels then their tools were a lot tougher than the pure copper the New England sculptor was using. I also read in anther article that for a period of time after the stone was first exposed to air after the major stone blocks were removed from the quarry they  were considerably softer than once they had cured in the sun where they became considerably harder. The article stated that most blocks for the pyramids were squared before leaving the quarry and some were shaped with flint scrapers. So it seems, now to me, that the program missed the point of carving the new "nose" with pure copper tools, they should have used a less than pure Calcolithic type of tooling to portray it more accurately.

[Frosty]

As much as I hate to say it, I've been a lot more impressed with the scientific research and approach of Mythbusters than Nova. From my exposure to prospecting with Father and that gang I'd venture to say, where you find copper you'll find: gold, silver, mercury, arsenic, nickle, tin and other metals close on the table.

 

I think the earliest cu tools were native copper (of course eh?) and refining cu came much later, same for iron. If a person were to try making tools using Egyptian glyphs as models you'd end up with nearly unworkable tools. The cu chisels as seen on Nova being a prime example, they were almost uselessly acute. Seriously, modern steel stone chisels aren't that narrow and tapered. All you need is to decrease the impact area to increase the psi and shock so the stone will fail. A fairly obtuse taper and an almost blunt point will have more effect.

 

Then we get to the techniques used by Egyptians who weren't that long out of the neolithic. There are glyphs showing steli, obelisks and such being quarried, shaped and polished with granite cobbles. We're not talking flaking/knapping, we're talking smash, grind and polish.

 

I'm thinking copper tools were used for saws and fine detail carvings, not the big stuff. The remains of plaster and paint remain on the sphinx so who was going to spend a lot of time and valuable tools on something that was going to get covered? Of course this may have been from another reign maybe decades to centuries after the original construction.

 

Of course those are just my opinions I could be wrong. <wink>

 

Frosty The Lucky.