Adding to what texasdreamer01 said, linsey-woolsey is a fabric which uses both flax and wool threads, with the advantages (and disadvantages) of both.

https://en.wikipedia.org/wiki/Linsey-woolsey

If a character wore a coat made with with linsey-woolsey, they'd probably not be a member of the Russian Jewish community, but would be more likely to have traditional Slavic religious practices or follow the relatively-new Russian Orthodox church. This could be part of the plot, particularly in a fantasy work where spells or supernatural creatures might work differently on different communities.