There's a book named The Phoenix and the Mirror by uhhh Davidson, I think? It's a weird mix of alt!antiquity and questing fantasy with magic and questionable gender mores (very classic sff, very dude), but there's a whole sequence in the first part of the book where the main character, an alchemist (and in this world alchemy actually works as intended), along with his colleagues and apprentices, creates a "pure mirror" - a mirror that's made of such alchemically pure materials that the very first person who looks into it will see their heart's desire or somesuch. and this sequence, described in loving and exhausting and practical detail, is GORGEOUS. it's my go-to example of how to ground and immerse the reader in the unfamiliar setting. i still remember the bits and pieces of the techniques they used, and the precautions they took, and the kilns they built for some of the steps, and so on. not quite by heart, but i can probably recreate a description if you took me some time with pen and paper - and the mirror is literally only needed for the quest, and the quest is so meh i to that day don't quite remember what the twist was about and why was it ever needed.