According to the assurances of Egyptologists, as well as tour guides in museums, (which is natural) - these artifacts are attributed to the period from 3100 - 2300 BC. made of … stone. Often the stone is "granite", black basalt, quartzite, obsidian, rocks that are difficult to process even with special steel tools.
Promotional video:
Traces of drilling are visible, during which the inside of this cover was made.
Something similar to our CDs in both shape and size. The material is very different, but there are only a couple of copper pieces, and those are of poor quality. The rest is from different types of stone. The discs increase slightly in thickness towards the center (edge 1-1.5 mm). Very symmetrical. With a clearly centered neat hole in the center.
A torus (or donut) cut lengthwise. Material - slate. The diameter is about 30 cm. On the inner radius, in one place, you can see the remnants of some kind of "petal" (not glued, but making up a single whole with one and a half !!!).
Vessels - "bulbs". Unfortunately, the photographs do not show that these stone containers (only 5-6 cm in size) are made with such precision that their walls are equidistant (i.e. have the same thickness everywhere), which can be seen when visually examining the broken vessels. Simply amazing mastery of performance!.. It is not clear what instrument could achieve such a result.
Here is a stone wheel. Not a work of art, not a household item. Most of all, it looks like some kind of technological detail. It was allegedly made by the ancient Egyptians. It is on display at the Cairo Museum as part of the Sakkar collection. The famous slate artifact with a functional purpose incomprehensible to Egyptologists. The size is impressive - the diameter is about 60 cm. The thickness of the "petals" is only 2-3 mm. The artifact has been restored from pieces, but it looks like the reconstruction was carried out quite correctly. “From the point of view of mathematics, this object is a circle in which a truncated three-ray hypocycloid is inscribed. But the item has an axis, which suggests that it rotated around its own axis when used. The axis does not go through the entire object, but ends in a spherical bottom.
Also, at first glance, it seems a mystery that the ancestors made jade (or from another stone) cylinders and tubes.
There were photographs of daggers and knives, the blades of which were made of jade.
Most of these products are not GPB castings, or imitations of natural stone. Layers of rock are visible on the items. Those. we can say that these are precisely natural rocks.
Even processing with simple iron will not give anything, the metal in these rocks can leave only slight scratches (or a trace like from a pencil on paper).
Only in our time have laboratory installations appeared that can drill, work in especially fragile materials using ultrasound:
But this is just drilling. And polishing is a separate topic, also a laborious and very time-consuming process.
Where are all those tools and equipment with which all these unique (even by our standards) artifacts were made? Having shown at least one instrument, historians will put a fat cross on all their bikes. I think they are, but showing them is strictly prohibited.
But there are products that closely resemble castings:
An artifact that was found in Colombia. This is the so-called "Genetic Disc". It is made of very strong Lidite stone. In terms of strength, it is not inferior to granite, but the structure of the stone is layered, so it is impossible to make such a disk from such a material these days. Diameter - 27cm.