Yeah they might try to look like how they could appear in game if they did, to which I think is pretty spot on. The November topaz looks like the gold nugget in ACNL, which is still yellow and topazs do come in yellow popularly. NL just missed coloured alot of their gems.
Rubies aren't pink, sapphires are typically a darker tone of blue, more like a true blue and darker (technically sapphires come in nearly all colours except red) amethyst is a little darker as well. Emerald, it's close but emeralds typically aren't that bright of green. Silver is prob the closest to the actual thing (even thou silver is a metal). Ignoring the opal because Opals have multiple and many colours in them, not only that but there are opals that are
a solid one colour. I do really like the blending in tbt's opal, it stands out lovely against the other gems.
I would do colour variants of the stones to look like how the gems appear irl myself if only I knew a thing about photo editing.
Yeah, I assume they want them in-game replicas or depiction but yeah since I love gemstones myself as well it just irks me d: