Torba and the synthesis of artificial rock
I am most intrigued by the material used in many of the Maltese temple floors. Torba, as it is called in Malta, has survived intact over 6,000 years in many sites around Malta. It is the earliest reference I have come across for a man made material that resembles rock. I don't know of any man made concrete or cement used today with comparable durability. Concrete typically last decades and crumbles over time. Trump 2002 P77 calls Torba a plaster-like material that '..sets hard and could be polished. The result can easily be mistaken for bedrock and in excavations it frequently is'. Plaster-like, in this context, I interpret to mean that the material was spread over a rough surface to smooth it out, just as plaster is usually applied over rough surfaces, and does not refer to its strength or durability, which is more like rock.
It seems that the archaeologists of Malta are of the opinion that Torba was formed by compacting crumbled rock and rock dust with simple tools, adding water, stomp, stomp and presto we have Torba, (Trump 2002 P77) possibly a tougher and more durable rock-like material than the best and strongest concrete used today. That may be true, but it may be more complex than that. Some knowledge of chemistry and cement also seems to be required. Certainly many Egyptian archaeologists are reluctant to believe that rock synthesis is possible. Please visit, (Joseph Davidovits) for more details of Egyptian rock synthesis. Certainly Davidovits does not have any explanation for the saw cuts and other advanced rock fabrication techniques that are evident in Egypt, but some of the finds there suggest that many rock structures there may have been cast. Davidovits calls his rock synthesis Geopolymer. A similar process may have been known by the temple builders of Malta.
In any case, there is very little doubt that the Torba rock-like material of Malta is man made. Other than Deffun, made of pottery sherds, I have no idea if other synthetic rock (~ concrete) was also made by these people. We may find that some of the limestone blocks in the temples are man made castings rather than real rock, though this is doubtful, and of course, the stone bowl found on Gozo at the Xarra Circle may be cast. The difference between natural vs artificial limestone blocks can be detected from the random orientation of shells and the greater porosity (lower compaction) of the man made material. If we can find Torba or other man made rock (~concrete) in the cart ruts.. (Temples probably got better treatment than cart ruts, so an inferior product may have been used) ..that would associate many of these interesting archaeological riddles together to a common culture and peoples. It would also greatly increase our appreciation for the capabilities and sophistication of the Maltese Temple People as we piece together their evolution of stone working technology and engineering.. ..an extraordinary skill and technology which we are only now beginning to rediscover Simply put, the prehistoric Maltese had technological rock working skills that are very impressive. It is time we accord them the respect they are due. I wonder what other great knowledge they possessed that has since been lost?