https://www.timesofisrael.com/tiny-3800-year-old-textile-found-in-israel-was-dyed-with-biblical-scarlet-worm/
Confirmed as using small insects for the dye - for your equally painstaking alternative to sea molluscs...
Nice shade of red.
Amazon order placed... :P
Good find. Interesting to see the colour only on one direction of the weave, emphasises the expense I expect.