Not quite like that at all. The Minoans were known to carve semi-precious gemstones and the Mycenaeans known to have adopted it from them from the 16th century

Not quite like that at all. The Minoans were known to carve semi-precious gemstones and the Mycenaeans known to have adopted it from them from the 16th century BC (source: "Encyclopedia of European Peoples, Vol 2, entry on "Mycenaeans", "Minoans: Life in Bronze Age Crete", R. Castleden). From Minoan sealstones which are already exhibited in museums, the level of detail seems comparable to me. I'm not quite sure where the contrast with classical Athens in the article comes from.