Sotah 48b states as follows:
'Rabbi Ami says: From the time when the First Temple was destroyed, shiny [peranda] silk [shira] and white glass ceased to exist. This is also taught in a baraita: From the time when the First Temple was destroyed, shiny silk, white glass, and iron chariots ceased...' The text goes on to also talk about certain foods also ceasing to exist, including the 'sweetness of honeycomb', congealed wine and/or 'nofet tzufim', an aspect of either honey or bread/flour. .
I've seen similar expressions about how a certain level or quality of brightness and colour being gone from the world since the fall of the temple(s) (can't find the references right now, will edit when I do). I understand some of these are probably metaphors for how the rabbis saw the world as darker/lesser/less directly 'in touch' with G-d's presence without the temple present (although some may have literally believed it altered the world's reality thus). But the comment about iron chariots seems oddly out of place, since it seems to talk about them as a thing themselves, rather than an aspect of them. Is it supposed to imply that chariots and/or iron likewise became less strong or splendid in quality after the temple's fall? That is assuming they ever existed as such in that era, since this is a well-known controversy, even within the span of the iron age: https://www.thetorah.com/article/the-history-of-iron-in-ancient-israel https://armstronginstitute.org/812-iron-chariots-a-biblical-impossibility
Or should we more likely understand it as a historical reference, since the iron age is typically considered to have ended around 550BC, with chariots falling out of (military) usage very shortly after (although still used for hunting and sport), and the first temple supposedly fell around 586/7 BCE? In which case, does anyone have any info on significant changes in food, fabric etc (trade, supplies, technique, etc) in the area at the time which might be related to what is being spoken of?