In Egypt, precious stones were called the stones of truth as they were transparent.
Soft stone, suitable for sculpting, was associated with evil and wrong as opposed to right, with stupidity, ignorance, error and lies.
Called Set, its determinant was a knife representing the idea of separation, cutting up, carving and division.
The god Set personified evil and this particular type of stone. He was sometimes represented by a donkey, and even today this animal evokes stubborn stupidity. He represented unfruitful, vile matter symbolised by the desert. The word has gone down the ages with little change as at the time it was written deshert.
All other stone was called in (pronounced ine). Reconstituted stone was called inir (consisting of in + ir, to create).
Hard stone (not cut, dressed or sculpted) symbolised truth and eternity.
In the ancient texts, the stones used in the pyramids were called eternal or truth stones which suggests that they had not been dressed or sculpted.
Was this perhaps the philosopher's stone that alchemists were seeking?