Promoting research, discussion, and debate about technologies used in Ancient Egypt

The Unfinished Obelisk at Aswan


Unfinished Ob with scallop marks

No printed records exist of the technology that was used to cut the massive obelisk blocks out of the quarry bedrock at the famous Aswan quarry. The only tangible evidence we have is in the form of the tool marks left on the surface of the quarry face after the blocks have been removed, some stratigraphic evidence of layers of burning and charcoal deposits, and a profusion of hand-sized rounded dolerite balls that littered the quarry floor.

Back in the 1920s, when this site was excavated by the English egyptologist Reginald Englebach, to reveal the now famous Unfinished Obelisk, he made a very simplistic assumption as to the extraction process in his publication The Problem of the Obelisks. As he could not see any of the usual ‘peck’ marks left from conventional chiseling, but there was a “proliferation” of rounded dolerite balls all over the floor of the quarry, he made one huge leap of an assumption in that they must have been used as ‘hand pounders’.   Pounders were indeed used in gold mines at that time, but for crushing the ore down to dust to extract the gold particles – not for the rock extraction – a totally different process.    This totally unproven and simplistic pounding theory, as applied to the extraction of the unfinished obelisk, was recorded in his paper and it is now endlessly repeated in every book and by every guide that shows you around that site.     Nobody questions this flawed theory; except people with a practical, engineering or scientific education where a simple examination of the evidence clearly shows that the pounding theory is scientifically unsustainable.

As can be seen in all the photos below, the quarry wall faces and the stumps on the quarry floor, left behind when the block was removed, show very regular ‘scallop’  marks everywhere and the unfinished obelisk gallery shows even more of these most enigmatic features. Each scallop has an almost uniform shallow curve profile that runs continuously down the walls and extends underneath the obelisk and ends up in cup-shaped hollows underneath the obelisk block.


To fully understand why the ‘pounding’ theory is so inappropriate one has to consider the process from both the quarry-man’s  and a forensic scientist’s points of view.

A rounded ball is the worst choice of shape to fracture granite.

To break up granite, even the Ancient Egyptians knew that they need a very sharp point and a heavy hammer to focus the energy into one very small area to overcome the strength of the quartz crystals and break off lumps of the stone i.e. chiseling, as done everywhere else on stone throughout the whole of Egypt.    So why would anyone chose a rounded ball which dissipates the energy over a very large area, creating nothing more than a small amount of dust?

Dolerite balls bounce on Granite.

Being so hard, both stones have a very high coefficient of restitution (‘bounce’).     For example, if you drop a hard golf ball onto a concrete floor it will bounce back up with nearly the same energy as you dropped it, with no energy imparted to the concrete.  Compare that with dropping a tennis ball on grass, where nearly all the energy is lost in distortion of the ball and in the impact on bending the blades of grass.   So, to understand this ‘pounding’ process better; when you are next on a beach, pick up a very hard, hand-sized pebble and bash it onto a bigger rock a hundered times and feel the reflected energy bounce back into your hand and wrist – I am sure you will not do it for more that a few minutes without giving up due to severe aches and pains.     Also, because you have to hold the ball by wrapping your fingers around the ball, how many times would you accidentally strike your fingers onto the rough granite; how many times would the ancient Egytptians do that without permanent crippling injuries?    Would any sensible stone mason do this for days, weeks, months or years needed to extract the obelisk?

The extraction rate would be far too slow.

I have searched the literature for a scientific measurement of the extraction rate that this process could achieve.    One or two people have made ad-hoc tests and made ‘guestimates’ of the extraction rates to try and support the Englebach theory.    All these trials actually show that the process is not viable.   As there is no hard scientific evidence in the literature, I carried out my own carefully controlled experiment.    Using a rounded dolerite pounder on a block of pink granite and pounding for 10 minutes created a lot of granite dust. Every fragment of the pounded granite was collected and weighed.    The extraction rate was only 1 gramme per minute which meant that even if I had all the men available that could be fitted into the obelisk trench to help me, it would still take 23 years using this method to extract the obelisk.  See full details in the research article Hand Pounding.

The Scallop marks are impossible to create by hand pounding.

These long, continuous and perfectly parallel scallop marks are supposed to be created, by default, by the endless pounding – downwards – on the bedrock floor by hitting in exactly the same place without any sideways deviation over the period of months of continuous pounding.  To create such geometric perfection by this process is clearly quite absurd.   However, suppose a new stonemason arrives at the site with the scallop marks already in front and on the floor below him.   Any sensible stonemason, armed with just a ball-shaped pounder would simply choose to strike sideways at the high-edged ridges, which would give way easily, rather than continue to beat downwards into the cup shaped hole where the powdered dust would absorb the impact.  Hand pounding would obliterate the perfectly regular scallop marks which are still visible after thousands of years.

Dust removal.

Pounding just creates lots of dust and this dust absorbs the energy of each blow.    This dust would fall onto the floor and just get in the way of the workers, so it would have to be continuously removed by men sweeping up the dust up into some form of bucket to be hauled out of the trench.  Look at the narrowness of the trench; can you imagine the chaos of this pounding, brushing and hauling in this confined space?

Sharp-sided deep holes.

Look at these very narrow deep holes that have perfectly straight sides, tight corner curves;  how could these have possibly be ‘hand pounded’?   Was the stonemason dangled by his ankles head-first into the bottom of the hole to do his pounding?  The idea is risible.   If the stonemasons had a special tool to cut these holes, surely that would use the same tool to do all the quarring?

‘Hand Pounding’, as an extraction process, simply cannot be the process used.

The Mindalah.

In my opinion, and also to other engineers who have really studied this problem, these marks are so clearly produced by the repeated action of fixed-shaped and precisely controlled tool – a corundum-tipped mechanism maybe, that two or three men would operate on a fixed frame to get stability and to be able to apply very high impact forces, rather like a giant chisel.   Even Englebach said that they must have employed a ‘mindalah’ (translated as ‘a granite rammer’) which he implied was a four-man machine; two to hold in position and two ‘to direct its blows’, but no desk research has ever thrown up any evidence of this device being described by anyone but Engleback.    However, I agree with Englebach on this point; such a machine must have been used and maybe one day, a tool like this, or evidence for one, will  be found.


Fire Setting.

Some authors, for example, James Harrell & Per Storemyr in Ancient Egyptian quarries – an illustrated overview, cite ‘fire setting’ as a process, combined with pounding, where the rough top surface of the granite is burnt with a hot fire.   Above 550 degrees Centigrade the quartz crystals form a new crystal structure which is slightly larger than in the cold state so they expand slightly and crack up when cooled down again. This makes the surface crumbly, like a digestive biscuit, and allows the stone surface to be easily pounded away with stones.   The effect only works down to the layer that did not reach this critical temperature and a typical example of a fire set stone surface is shown in the photo.   It is a very crude process and requires a huge amount of wood to get the temperature up to 550 degrees C. This process could only be considered as a method for the gross removal of over-burden, not as a precise process needed for trenching around the obelisk block because there would also be far too much danger of degrading the obelisk surface as the flames rose up out of the narrow trench.    Fire setting on the bulk removal of the over-burden explains the charcoal layers found in the debis on the quarry site.

The Dolerite Balls?


What about those dolerite balls, that were found by Engelbach in ‘profusion’ on the quarry floor?  If they were not there for pounding what were they doing there?    They clearly had a purpose.    Some commentators in trying to justify Englebachs theory state that they have bee ‘fashioned’ to make smooth hand pounders – no, these dolerite balls occur naturally in the granite bedrock in rounded ball shapes (see photo) within the granite bedrock and were found in ‘abundance’ in the river Nile in the Aswan area, and in the cataracts near Aswan.  A far more likely use for these rounded pebbles is that they were used as ball bearings to absorb the impact of the extracted blocks when finally broken off from their bases and were then used to help transport the blocks around the quarry and down to the banks of the Nile, as illustrated in the diagram below.  How else would the quarrymen manoeuvre huge blocks of granite down to the Nile?


What really was the method used to extract the blocks?

Unfortunately, with Englebach’s pounding theory so prevalent over the past one hundred years, it has prevented people really thinking about the evidence that is in evidence all around the quarry.    By analysing the scientific facts, as discussed above, hopefully there will now be more attention to finding out more about the possible real procees used and the ‘Mindalah’ machine that must have been the method used.   This will be the focus of further research on this website.


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