And not just transistors, but analog circuits as well, allowing for extremely compact designs.
But who knows with quantum photonics, maybe laser/optic circuits will supplant a large chunk of silicon transistors in the next 100 years
But Stone/Copper/Bronze/Iron refer specifically to the dominant material for crafting weaponry. In that sense, maybe we're in the transition between Steel and Plastic, though maybe a case could be made for Lead.
Or we really are in the Nuclear Age, and it becomes the Final Age of Humanity.
Or war has gone digital, and we are in the Information Age, beyond terrestrial materials. In that case, true Space and then Atomic (universal assembler) Ages may follow.
Silicon is present in sand, so we’ve been using it forever in ceramics, on some level. Like copper, it has been a good friend to humanity for a very long time. The only problem is that “using lots of SI” is not a distinguishing characteristic for an age!
We call it the Iron Age because iron is a grumpy, unfriendly element that didn’t want to help out until we got some pretty fancy forges.
Maybe we could use it to mark some larger scales. Silicon age could start around 25k years ago with the invention of pottery. Before that, I dunno, fire age or rock age.