Part of the ‘Antique Fabrics’ series, this fabric isn’t necessarily extinct, but it was more popular in the past than the present.
Covert coats are mentioned in 19th century catalogs as outdoor garments suitable for hunters and offered in colors designed to blend in with the countryside.
Covert cloth is still made today, sometimes with wool, but also cotton or wool blends, and in lighter weights than its 19th century counterpart. Covert coats are apparently still a thing in some circles, although I suspect they cost a fortune. And if that coat is lighter in weight than its 19th century counterpart, the originals must have been fiercely robust!
I went hunting for covert yardage, but couldn’t find anything that I’d flat out call covert, rather than just “country tweed”. The big difference between covert and a regular tweed is the fact that the covert is water resistant. I would guess that the price for such a fabric would start at $30/yd and go up from there, potentially to over a hundred dollars per yard.
As per the historical fabric, use covert for overcoats or cloaks – possibly trousers if you want to look particularly sporting. Sew it with a heavy needle and all-purpose thread. Use a rolling foot to tackle bulky seams.
As per any wool fabric, hand wash it in cold water, or send it to the dry cleaner and never, ever put it in your dryer. Lay it flat to dry, or drape it over a clothes horse. I wouldn’t put it on a single washing line, lest it leave a permanent mark from the weight of the wet material.
For a good-enough substitute, consider any wool or wool-poly tweed in countryside-friendly colors.