They had a goldsmithing technique that is unrivaled as well...some beautiful work in gold...
I don't agree it's "unrivaled" but it took many years for modern artisans to learn how the Etruscans did it. The technique is called "granulation" and involves affixing masses of very tiny gold spheres on golden bowls, vases, etc. to create intricate dimensional patterns.
There were two basic mysteries: how they made the spheres in such uniform sizes and how they attached them to the gold vessels without using solder of any kind. The heating methods available to them were very primitive by modern standards.
While modern goldsmiths have learned the answers and can now duplicate the process, they are still amazed the Etruscans were able to do such fine work without electronically-controlled ovens, etc. But I've seen examples of granulation work far older than Etruscan work in museums and have concluded they had merely refined a very ancient technique.
I remember reading somewhere that the riddle of the Etruscans' origin had been resolved. IIRC they were a remnant of a culture based in Anatolia that could no longer support them due to some calamity: drought, war, can't recall exactly. They were sent off by sea to find a new place to live and arrived in Italy with all their prior knowledge intact: metal smithing, civil engineering, cultural traditions, etc. I'll see if I can relocate that reference. I've been intrigued by them for years.